test: add automated tests for word tracking, frame sequencing, and Cartesia TTS

Adds tests for AggregatedFrameSequencer, WordCompletionTracker, and
word_timestamp_utils (including CJK language scenarios). Updates existing
Cartesia TTS and TTS frame ordering tests to cover the new behaviours.

tests/test_aggregated_frame_sequencer.py

@@ -0,0 +1,612 @@
+#
+# Copyright (c) 2024-2026, Daily
+#
+# SPDX-License-Identifier: BSD 2-Clause License
+#
+
+"""Tests for AggregatedFrameSequencer.
+
+All methods on the sequencer are synchronous and return lists of frames,
+so no async machinery is needed here.
+
+Test groups:
+- register_skipped: immediate flush vs. blocked by a preceding spoken slot
+- register_spoken / complete_spoken_slot: push_text_frames=True path
+- flush: pts propagation, transport_destination, stops at incomplete spoken slot
+- process_word: normal, completing, passthrough, raw_text propagation
+- process_word overflow: single token spanning two slot boundaries
+- process_word force-complete via belongs_here failure
+- force_complete: remaining text emission, raw_text, corrupt raw discard, slot ordering
+- clear: resets all state
+"""
+
+import unittest
+
+from pipecat.frames.frames import AggregatedTextFrame, AggregationType, TTSTextFrame
+from pipecat.utils.context.aggregated_frame_sequencer import AggregatedFrameSequencer
+from pipecat.utils.context.word_completion_tracker import WordCompletionTracker
+
+# ---------------------------------------------------------------------------
+# Helpers
+# ---------------------------------------------------------------------------
+
+
+def _seq() -> AggregatedFrameSequencer:
+    return AggregatedFrameSequencer(name="test")
+
+
+def _spoken_frame(text: str) -> AggregatedTextFrame:
+    return AggregatedTextFrame(text, AggregationType.SENTENCE)
+
+
+def _skipped_frame(text: str) -> AggregatedTextFrame:
+    return AggregatedTextFrame(text, "code")
+
+
+def _tracker(tts_text: str, llm_text: str | None = None) -> WordCompletionTracker:
+    return WordCompletionTracker(tts_text, llm_text=llm_text)
+
+
+# ---------------------------------------------------------------------------
+# register_skipped
+# ---------------------------------------------------------------------------
+
+
+class TestRegisterSkipped(unittest.TestCase):
+    def test_emits_immediately_with_empty_queue(self):
+        seq = _seq()
+        frame = _skipped_frame("code block")
+        result = seq.register_skipped(frame, "ctx1", None)
+        self.assertEqual(len(result), 1)
+        self.assertIs(result[0], frame)
+
+    def test_sets_append_to_context_true(self):
+        seq = _seq()
+        frame = _skipped_frame("code")
+        seq.register_skipped(frame, "ctx1", None)
+        self.assertTrue(frame.append_to_context)
+
+    def test_sets_context_id_on_frame(self):
+        seq = _seq()
+        frame = _skipped_frame("code")
+        seq.register_skipped(frame, "ctx42", None)
+        self.assertEqual(frame.context_id, "ctx42")
+
+    def test_sets_transport_destination(self):
+        seq = _seq()
+        frame = _skipped_frame("code")
+        result = seq.register_skipped(frame, "ctx1", "dest-A")
+        self.assertEqual(result[0].transport_destination, "dest-A")
+
+    def test_blocked_by_incomplete_spoken_slot(self):
+        seq = _seq()
+        seq.register_spoken(_spoken_frame("hello world"), "ctx1", _tracker("hello world"), True)
+        result = seq.register_skipped(_skipped_frame("code"), "ctx2", None)
+        self.assertEqual(result, [])
+
+    def test_emits_immediately_after_already_complete_spoken_slot(self):
+        seq = _seq()
+        seq.register_spoken(_spoken_frame("hi"), "ctx1", tracker=None, append_to_context=True)
+        seq.complete_spoken_slot()
+        result = seq.register_skipped(_skipped_frame("code"), "ctx2", None)
+        self.assertEqual(len(result), 1)
+
+    def test_multiple_skipped_before_any_spoken_all_emit(self):
+        seq = _seq()
+        r1 = seq.register_skipped(_skipped_frame("code1"), "ctx1", None)
+        r2 = seq.register_skipped(_skipped_frame("code2"), "ctx2", None)
+        self.assertEqual(len(r1), 1)
+        self.assertEqual(len(r2), 1)
+
+
+# ---------------------------------------------------------------------------
+# register_spoken / complete_spoken_slot  (push_text_frames=True path)
+# ---------------------------------------------------------------------------
+
+
+class TestCompleteSpokenSlot(unittest.TestCase):
+    def test_noop_with_empty_queue(self):
+        seq = _seq()
+        self.assertEqual(seq.complete_spoken_slot(), [])
+
+    def test_marks_slot_complete_and_flushes_skipped(self):
+        seq = _seq()
+        seq.register_spoken(_spoken_frame("hello"), "ctx1", tracker=None, append_to_context=True)
+        skipped = _skipped_frame("code")
+        seq.register_skipped(skipped, "ctx2", None)  # blocked
+
+        result = seq.complete_spoken_slot()
+        self.assertEqual(len(result), 1)
+        self.assertIs(result[0], skipped)
+        self.assertTrue(skipped.append_to_context)
+
+    def test_only_first_pending_slot_is_marked(self):
+        seq = _seq()
+        seq.register_spoken(_spoken_frame("one"), "ctx1", tracker=None, append_to_context=True)
+        seq.register_spoken(_spoken_frame("two"), "ctx2", tracker=None, append_to_context=True)
+        skipped = _skipped_frame("code")
+        seq.register_skipped(skipped, "ctx3", None)
+
+        # ctx2 still blocks the skipped frame
+        result = seq.complete_spoken_slot()
+        self.assertEqual(result, [])
+
+    def test_skipped_flushes_after_all_preceding_spoken_complete(self):
+        seq = _seq()
+        seq.register_spoken(_spoken_frame("one"), "ctx1", tracker=None, append_to_context=True)
+        seq.register_spoken(_spoken_frame("two"), "ctx2", tracker=None, append_to_context=True)
+        skipped = _skipped_frame("code")
+        seq.register_skipped(skipped, "ctx3", None)
+
+        seq.complete_spoken_slot()  # completes ctx1
+        result = seq.complete_spoken_slot()  # completes ctx2 → flush skipped
+        self.assertEqual(len(result), 1)
+        self.assertIs(result[0], skipped)
+
+
+# ---------------------------------------------------------------------------
+# flush
+# ---------------------------------------------------------------------------
+
+
+class TestFlush(unittest.TestCase):
+    def test_empty_queue_returns_empty(self):
+        self.assertEqual(_seq().flush(), [])
+
+    def test_stops_at_incomplete_spoken_slot(self):
+        seq = _seq()
+        seq.register_spoken(_spoken_frame("hello"), "ctx1", tracker=None, append_to_context=True)
+        seq.register_skipped(_skipped_frame("code"), "ctx2", None)
+        self.assertEqual(seq.flush(), [])
+
+    def test_last_word_pts_assigned_to_skipped_frame(self):
+        seq = _seq()
+        seq.register_spoken(_spoken_frame("hello"), "ctx1", _tracker("hello"), True)
+        skipped = _skipped_frame("code")
+        seq.register_skipped(skipped, "ctx2", None)
+
+        # process_word("hello") completes the spoken slot and calls flush(last_word_pts=77)
+        result = seq.process_word("hello", pts=77, context_id="ctx1")
+        flushed = [f for f in result if isinstance(f, AggregatedTextFrame) and f.text == "code"]
+        self.assertEqual(len(flushed), 1)
+        self.assertEqual(flushed[0].pts, 77)
+
+    def test_complete_spoken_slots_are_swept(self):
+        seq = _seq()
+        seq.register_spoken(_spoken_frame("hello"), "ctx1", tracker=None, append_to_context=True)
+        seq.complete_spoken_slot()
+        # Queue should be empty after sweeping the complete spoken slot
+        self.assertEqual(seq._slots, [])
+
+
+# ---------------------------------------------------------------------------
+# process_word — basic
+# ---------------------------------------------------------------------------
+
+
+class TestProcessWordBasic(unittest.TestCase):
+    def _seq_with_spoken(self, text: str, ctx: str = "ctx1", append: bool = True):
+        seq = _seq()
+        seq.register_spoken(_spoken_frame(text), ctx, _tracker(text), append)
+        return seq
+
+    def test_returns_tts_text_frame(self):
+        seq = self._seq_with_spoken("hello")
+        result = seq.process_word("hello", pts=100, context_id="ctx1")
+        self.assertEqual(len(result), 1)
+        self.assertIsInstance(result[0], TTSTextFrame)
+
+    def test_frame_text_and_pts(self):
+        seq = self._seq_with_spoken("hello")
+        result = seq.process_word("hello", pts=100, context_id="ctx1")
+        self.assertEqual(result[0].text, "hello")
+        self.assertEqual(result[0].pts, 100)
+
+    def test_frame_context_id(self):
+        seq = self._seq_with_spoken("hello", ctx="ctx99")
+        result = seq.process_word("hello", pts=1, context_id="ctx99")
+        self.assertEqual(result[0].context_id, "ctx99")
+
+    def test_append_to_context_true(self):
+        seq = self._seq_with_spoken("hello", append=True)
+        result = seq.process_word("hello", pts=1, context_id="ctx1")
+        self.assertTrue(result[0].append_to_context)
+
+    def test_append_to_context_false(self):
+        seq = self._seq_with_spoken("hello", append=False)
+        result = seq.process_word("hello", pts=1, context_id="ctx1")
+        self.assertFalse(result[0].append_to_context)
+
+    def test_non_completing_word_does_not_flush_skipped(self):
+        seq = self._seq_with_spoken("hello world")
+        seq.register_skipped(_skipped_frame("code"), "ctx2", None)
+        result = seq.process_word("hello", pts=10, context_id="ctx1")
+        self.assertEqual(len(result), 1)
+        self.assertIsInstance(result[0], TTSTextFrame)
+
+    def test_completing_word_flushes_blocked_skipped_frame(self):
+        seq = self._seq_with_spoken("hello")
+        skipped = _skipped_frame("code")
+        seq.register_skipped(skipped, "ctx2", None)
+        result = seq.process_word("hello", pts=50, context_id="ctx1")
+        self.assertEqual(len(result), 2)
+        self.assertIsInstance(result[0], TTSTextFrame)
+        self.assertIs(result[1], skipped)
+
+    def test_last_of_multiple_words_flushes_skipped(self):
+        seq = self._seq_with_spoken("hello world")
+        skipped = _skipped_frame("code")
+        seq.register_skipped(skipped, "ctx2", None)
+        seq.process_word("hello", pts=10, context_id="ctx1")
+        result = seq.process_word("world", pts=20, context_id="ctx1")
+        self.assertTrue(any(f is skipped for f in result))
+
+    def test_no_active_slot_emits_passthrough(self):
+        seq = _seq()
+        result = seq.process_word("hello", pts=1, context_id="ctx-unknown")
+        self.assertEqual(len(result), 1)
+        self.assertIsInstance(result[0], TTSTextFrame)
+        self.assertEqual(result[0].text, "hello")
+        self.assertEqual(result[0].context_id, "ctx-unknown")
+
+    def test_passthrough_uses_default_append_to_context_true(self):
+        seq = _seq()
+        result = seq.process_word("hello", pts=1, context_id="ctx-unknown")
+        self.assertTrue(result[0].append_to_context)
+
+    def test_unrecognised_word_emits_passthrough(self):
+        seq = _seq()
+        seq.register_spoken(_spoken_frame("hello world"), "ctx1", _tracker("hello world"), True)
+        # "zzz" doesn't belong to "hello world" and there is no next slot
+        result = seq.process_word("zzz", pts=5, context_id="ctx1")
+        self.assertEqual(len(result), 1)
+        self.assertEqual(result[0].text, "zzz")
+
+
+# ---------------------------------------------------------------------------
+# process_word — raw_text propagation
+# ---------------------------------------------------------------------------
+
+
+class TestProcessWordRawText(unittest.TestCase):
+    def test_raw_text_split_across_word_frames(self):
+        seq = _seq()
+        seq.register_spoken(
+            _spoken_frame("4111 1111"),
+            "ctx1",
+            WordCompletionTracker("4111 1111", llm_text="<card>4111 1111</card>"),
+            append_to_context=True,
+        )
+        r1 = seq.process_word("4111", pts=10, context_id="ctx1")
+        r2 = seq.process_word("1111", pts=20, context_id="ctx1")
+        self.assertEqual(r1[0].raw_text, "<card>4111")
+        last_word_frames = [f for f in r2 if isinstance(f, TTSTextFrame)]
+        self.assertEqual(last_word_frames[0].raw_text, "1111</card>")
+
+    def test_raw_text_none_when_no_llm_text(self):
+        seq = _seq()
+        seq.register_spoken(_spoken_frame("hello"), "ctx1", _tracker("hello"), True)
+        result = seq.process_word("hello", pts=1, context_id="ctx1")
+        self.assertIsNone(result[0].raw_text)
+
+
+# ---------------------------------------------------------------------------
+# process_word — overflow (single token spanning two slots)
+# ---------------------------------------------------------------------------
+
+
+class TestProcessWordOverflow(unittest.TestCase):
+    def test_overflow_produces_two_tts_text_frames(self):
+        seq = _seq()
+        seq.register_spoken(_spoken_frame("abc"), "ctx1", _tracker("abc"), True)
+        seq.register_spoken(_spoken_frame("def"), "ctx2", _tracker("def"), True)
+
+        result = seq.process_word("abcdef", pts=100, context_id="ctx1")
+        word_frames = [f for f in result if isinstance(f, TTSTextFrame)]
+        self.assertEqual(len(word_frames), 2)
+        self.assertEqual(word_frames[0].text, "abc")
+        self.assertEqual(word_frames[1].text, "def")
+
+    def test_overflow_assigns_correct_context_ids(self):
+        seq = _seq()
+        seq.register_spoken(_spoken_frame("abc"), "ctx1", _tracker("abc"), True)
+        seq.register_spoken(_spoken_frame("def"), "ctx2", _tracker("def"), True)
+
+        result = seq.process_word("abcdef", pts=100, context_id="ctx1")
+        word_frames = [f for f in result if isinstance(f, TTSTextFrame)]
+        self.assertEqual(word_frames[0].context_id, "ctx1")
+        self.assertEqual(word_frames[1].context_id, "ctx2")
+
+    def test_overflow_completing_next_slot_flushes_skipped(self):
+        seq = _seq()
+        seq.register_spoken(_spoken_frame("abc"), "ctx1", _tracker("abc"), True)
+        seq.register_spoken(_spoken_frame("def"), "ctx2", _tracker("def"), True)
+        skipped = _skipped_frame("code")
+        seq.register_skipped(skipped, "ctx3", None)  # blocked behind ctx2
+
+        result = seq.process_word("abcdef", pts=100, context_id="ctx1")
+        self.assertTrue(any(f is skipped for f in result))
+
+    def test_overflow_not_completing_next_slot_does_not_flush_skipped(self):
+        seq = _seq()
+        seq.register_spoken(_spoken_frame("abc"), "ctx1", _tracker("abc"), True)
+        seq.register_spoken(_spoken_frame("def ghi"), "ctx2", _tracker("def ghi"), True)
+        skipped = _skipped_frame("code")
+        seq.register_skipped(skipped, "ctx3", None)
+
+        # "abcdef" overflows: "def" goes to ctx2, but ctx2 still expects " ghi"
+        result = seq.process_word("abcdef", pts=100, context_id="ctx1")
+        self.assertFalse(any(f is skipped for f in result))
+
+
+# ---------------------------------------------------------------------------
+# process_word — force-complete via word_belongs_here failure
+# ---------------------------------------------------------------------------
+
+
+class TestProcessWordForcesComplete(unittest.TestCase):
+    def test_word_for_next_slot_force_completes_current(self):
+        """When a word belongs to the next slot but not the current, the current
+        slot is force-completed and the word is routed to the next slot."""
+        seq = _seq()
+        seq.register_spoken(_spoken_frame("hello"), "ctx1", _tracker("hello"), True)
+        seq.register_spoken(_spoken_frame("world"), "ctx2", _tracker("world"), True)
+
+        # "world" doesn't belong to ctx1 but belongs to ctx2
+        result = seq.process_word("world", pts=50, context_id="ctx2")
+        word_frames = [f for f in result if isinstance(f, TTSTextFrame)]
+        texts = {f.text for f in word_frames}
+        self.assertIn("world", texts)
+
+    def test_force_complete_then_overflow_flushes_skipped(self):
+        seq = _seq()
+        seq.register_spoken(_spoken_frame("hello"), "ctx1", _tracker("hello"), True)
+        seq.register_spoken(_spoken_frame("world"), "ctx2", _tracker("world"), True)
+        skipped = _skipped_frame("code")
+        seq.register_skipped(skipped, "ctx3", None)
+
+        # "world" force-completes ctx1 and completes ctx2 via overflow
+        result = seq.process_word("world", pts=50, context_id="ctx2")
+        self.assertTrue(any(f is skipped for f in result))
+
+
+# ---------------------------------------------------------------------------
+# force_complete
+# ---------------------------------------------------------------------------
+
+
+class TestForceComplete(unittest.TestCase):
+    def test_emits_remaining_text_when_word_dropped(self):
+        seq = _seq()
+        seq.register_spoken(_spoken_frame("hello world"), "ctx1", _tracker("hello world"), True)
+        seq.process_word("hello", pts=10, context_id="ctx1")  # "world" never arrives
+
+        result = seq.force_complete(last_word_pts=50)
+        tts_frames = [f for f in result if isinstance(f, TTSTextFrame)]
+        self.assertEqual(len(tts_frames), 1)
+        self.assertEqual(tts_frames[0].text, "world")
+        self.assertEqual(tts_frames[0].pts, 50)
+
+    def test_emits_full_text_when_no_words_arrived(self):
+        seq = _seq()
+        seq.register_spoken(_spoken_frame("hello world"), "ctx1", _tracker("hello world"), True)
+
+        result = seq.force_complete(last_word_pts=0)
+        tts_frames = [f for f in result if isinstance(f, TTSTextFrame)]
+        self.assertEqual(len(tts_frames), 1)
+        self.assertEqual(tts_frames[0].text, "hello world")
+
+    def test_already_complete_slot_emits_nothing(self):
+        seq = _seq()
+        seq.register_spoken(_spoken_frame("hi"), "ctx1", _tracker("hi"), True)
+        seq.process_word("hi", pts=5, context_id="ctx1")  # completes normally
+
+        result = seq.force_complete(last_word_pts=10)
+        self.assertEqual(result, [])
+
+    def test_flushes_skipped_frames_after_completing(self):
+        seq = _seq()
+        seq.register_spoken(_spoken_frame("hello"), "ctx1", _tracker("hello"), True)
+        skipped = _skipped_frame("code")
+        seq.register_skipped(skipped, "ctx2", None)
+
+        result = seq.force_complete(last_word_pts=20)
+        self.assertTrue(any(f is skipped for f in result))
+        self.assertTrue(skipped.append_to_context)
+
+    def test_propagates_raw_text(self):
+        seq = _seq()
+        seq.register_spoken(
+            _spoken_frame("4111 1111"),
+            "ctx1",
+            WordCompletionTracker("4111 1111", llm_text="<card>4111 1111</card>"),
+            append_to_context=True,
+        )
+        seq.process_word("4111", pts=10, context_id="ctx1")  # "1111" never arrives
+
+        result = seq.force_complete(last_word_pts=20)
+        tts_frames = [f for f in result if isinstance(f, TTSTextFrame)]
+        self.assertEqual(tts_frames[0].text, "1111")
+        self.assertEqual(tts_frames[0].raw_text, "1111</card>")
+
+    def test_discards_corrupt_raw_remaining(self):
+        """raw_remaining is discarded when it does not contain remaining_text."""
+        seq = _seq()
+        # "abc" normalized ≠ "xyz" normalized — any remaining won't be in raw_remaining
+        seq.register_spoken(
+            _spoken_frame("abc"),
+            "ctx1",
+            WordCompletionTracker("abc", llm_text="xyz"),
+            append_to_context=True,
+        )
+        result = seq.force_complete(last_word_pts=0)
+        tts_frames = [f for f in result if isinstance(f, TTSTextFrame)]
+        self.assertEqual(len(tts_frames), 1)
+        self.assertEqual(tts_frames[0].text, "abc")
+        self.assertIsNone(tts_frames[0].raw_text)  # discarded due to corruption
+
+    def test_slot_without_tracker_just_marks_complete_and_flushes(self):
+        seq = _seq()
+        seq.register_spoken(_spoken_frame("hello"), "ctx1", tracker=None, append_to_context=True)
+        skipped = _skipped_frame("code")
+        seq.register_skipped(skipped, "ctx2", None)
+
+        result = seq.force_complete(last_word_pts=0)
+        tts_frames = [f for f in result if isinstance(f, TTSTextFrame)]
+        self.assertEqual(tts_frames, [])  # no tracker → no word frame
+        self.assertTrue(any(f is skipped for f in result))
+
+    def test_multiple_incomplete_slots_all_emitted(self):
+        seq = _seq()
+        seq.register_spoken(_spoken_frame("hello"), "ctx1", _tracker("hello"), True)
+        seq.register_spoken(_spoken_frame("world"), "ctx2", _tracker("world"), True)
+
+        result = seq.force_complete(last_word_pts=0)
+        tts_frames = [f for f in result if isinstance(f, TTSTextFrame)]
+        texts = {f.text for f in tts_frames}
+        self.assertIn("hello", texts)
+        self.assertIn("world", texts)
+
+
+# ---------------------------------------------------------------------------
+# clear
+# ---------------------------------------------------------------------------
+
+
+class TestClear(unittest.TestCase):
+    def test_clears_slots(self):
+        seq = _seq()
+        seq.register_spoken(_spoken_frame("hello"), "ctx1", _tracker("hello"), True)
+        seq.register_skipped(_skipped_frame("code"), "ctx2", None)
+        seq.clear()
+        self.assertEqual(seq._slots, [])
+
+    def test_clears_context_map(self):
+        seq = _seq()
+        seq.register_spoken(_spoken_frame("hello"), "ctx1", _tracker("hello"), True)
+        seq.clear()
+        self.assertEqual(seq._context_append_to_context, {})
+
+    def test_after_clear_skipped_emits_immediately(self):
+        seq = _seq()
+        seq.register_spoken(_spoken_frame("hello"), "ctx1", _tracker("hello"), True)
+        seq.clear()
+        frame = _skipped_frame("code")
+        result = seq.register_skipped(frame, "ctx2", None)
+        self.assertEqual(len(result), 1)
+
+    def test_after_clear_process_word_uses_passthrough(self):
+        seq = _seq()
+        seq.register_spoken(_spoken_frame("hello"), "ctx1", _tracker("hello"), True)
+        seq.clear()
+        result = seq.process_word("hello", pts=1, context_id="ctx1")
+        # No active slot after clear → passthrough
+        self.assertEqual(len(result), 1)
+        self.assertEqual(result[0].text, "hello")
+
+
+# ---------------------------------------------------------------------------
+# CJK languages — Korean, Japanese, Chinese
+# ---------------------------------------------------------------------------
+
+
+class TestCJKLanguages(unittest.TestCase):
+    """Sequencer behaviour for CJK language scenarios.
+
+    Korean: Cartesia returns each word as a separate timestamp event (one word
+    per process_word call).  Japanese/Chinese: Cartesia merges all characters
+    in one timestamp message into a single combined token before calling
+    process_word.
+    """
+
+    # --- Korean ---
+
+    def test_korean_word_by_word_completes_slot_and_flushes_skipped(self):
+        """Korean words fed one at a time complete the spoken slot and unblock a skipped frame."""
+        seq = _seq()
+        sentence = "저는 여러분의 AI 어시스턴트입니다."
+        words = ["저는", "여러분의", "AI", "어시스턴트입니다."]
+        seq.register_spoken(_spoken_frame(sentence), "ctx1", _tracker(sentence), True)
+        skipped = _skipped_frame("[code]")
+        seq.register_skipped(skipped, "ctx2", None)
+
+        # Skipped stays blocked until the last word arrives
+        for word in words[:-1]:
+            partial = seq.process_word(word, pts=100, context_id="ctx1")
+            self.assertFalse(any(f is skipped for f in partial))
+
+        result = seq.process_word(words[-1], pts=200, context_id="ctx1")
+        self.assertTrue(any(f is skipped for f in result))
+
+    def test_korean_force_complete_emits_correct_remaining_text(self):
+        """After one Korean word, force_complete emits the correct unspoken suffix."""
+        seq = _seq()
+        sentence = "저는 여러분의 AI 어시스턴트입니다."
+        seq.register_spoken(_spoken_frame(sentence), "ctx1", _tracker(sentence), True)
+        seq.process_word("저는", pts=10, context_id="ctx1")
+
+        result = seq.force_complete(last_word_pts=50)
+        tts_frames = [f for f in result if isinstance(f, TTSTextFrame)]
+        self.assertEqual(len(tts_frames), 1)
+        self.assertEqual(tts_frames[0].text, "여러분의 AI 어시스턴트입니다.")
+        self.assertEqual(tts_frames[0].pts, 50)
+
+    # --- Japanese ---
+
+    def test_japanese_combined_groups_complete_spoken_slot(self):
+        """Two Cartesia-style combined Japanese groups complete the slot and flush skipped."""
+        seq = _seq()
+        sentence = "こんにちは、私はあなたの"
+        seq.register_spoken(_spoken_frame(sentence), "ctx1", _tracker(sentence), True)
+        skipped = _skipped_frame("[skipped]")
+        seq.register_skipped(skipped, "ctx2", None)
+
+        r1 = seq.process_word("こんにちは、私", pts=100, context_id="ctx1")
+        self.assertFalse(any(f is skipped for f in r1))
+
+        r2 = seq.process_word("はあなたの", pts=200, context_id="ctx1")
+        self.assertTrue(any(f is skipped for f in r2))
+
+    def test_japanese_force_complete_emits_remaining_chars(self):
+        """After the first Japanese combined group, force_complete emits the rest."""
+        seq = _seq()
+        sentence = "こんにちは、私はあなたの"
+        seq.register_spoken(_spoken_frame(sentence), "ctx1", _tracker(sentence), True)
+        seq.process_word("こんにちは、私", pts=10, context_id="ctx1")
+
+        result = seq.force_complete(last_word_pts=50)
+        tts_frames = [f for f in result if isinstance(f, TTSTextFrame)]
+        self.assertEqual(len(tts_frames), 1)
+        self.assertEqual(tts_frames[0].text, "はあなたの")
+
+    # --- Chinese ---
+
+    def test_chinese_combined_groups_complete_spoken_slot(self):
+        """Two Cartesia-style combined Chinese groups complete the slot and flush skipped."""
+        seq = _seq()
+        sentence = "你好，我是你的智能"
+        seq.register_spoken(_spoken_frame(sentence), "ctx1", _tracker(sentence), True)
+        skipped = _skipped_frame("[skipped]")
+        seq.register_skipped(skipped, "ctx2", None)
+
+        r1 = seq.process_word("你好，我是", pts=100, context_id="ctx1")
+        self.assertFalse(any(f is skipped for f in r1))
+
+        r2 = seq.process_word("你的智能", pts=200, context_id="ctx1")
+        self.assertTrue(any(f is skipped for f in r2))
+
+    def test_chinese_force_complete_emits_remaining_chars(self):
+        """After the first Chinese combined group, force_complete emits the rest."""
+        seq = _seq()
+        sentence = "你好，我是你的智能"
+        seq.register_spoken(_spoken_frame(sentence), "ctx1", _tracker(sentence), True)
+        seq.process_word("你好，我是", pts=10, context_id="ctx1")
+
+        result = seq.force_complete(last_word_pts=50)
+        tts_frames = [f for f in result if isinstance(f, TTSTextFrame)]
+        self.assertEqual(len(tts_frames), 1)
+        self.assertEqual(tts_frames[0].text, "你的智能")
+
+
+if __name__ == "__main__":
+    unittest.main()

tests/test_cartesia_tts.py

@@ -18,7 +18,7 @@ def _service(language: str) -> CartesiaTTSService:
 def _process_word_timestamps(
     words: list[str], starts: list[float], language: str
 ) -> list[tuple[str, float]]:
-    return _service(language)._process_word_timestamps_for_language(words, starts)
+    return _service(language)._normalize_word_timestamps(words, starts)
 
 
 def _concatenate_processed_timestamps(
@@ -27,7 +27,7 @@ def _concatenate_processed_timestamps(
     service = _service(language)
     text_parts = []
     for words, starts in timestamp_groups:
-        processed_timestamps = service._process_word_timestamps_for_language(words, starts)
+        processed_timestamps = service._normalize_word_timestamps(words, starts)
         includes_inter_frame_spaces = service._word_timestamps_include_inter_frame_spaces()
         text_parts.extend(
             TextPartForConcatenation(

tests/test_tts_frame_ordering.py

@@ -21,6 +21,13 @@ repeated for each TTSSpeakFrame, with no cross-group contamination.
 Also covers LLM response flow with push_text_frames=True (non-word-timestamp TTS):
 verifies TTSTextFrame ordering relative to LLMFullResponseEndFrame.
 
+Also covers smart-text / WordCompletionTracker features:
+- Skipped frames (skip_aggregator_types) held until preceding spoken slots complete.
+- raw_text on AggregatedTextFrame propagated as spans to TTSTextFrames.
+- Overflow: a single TTS word straddling two AggregatedTextFrame boundaries produces
+  two correctly-attributed TTSTextFrames.
+- Force-complete safety net: skipped frames flush even when TTS drops word timestamps.
+
 Also covers the interruption-during-pause deadlock scenario (see test_no_deadlock_on_interrupt_*).
 """
 
@@ -50,6 +57,7 @@ from pipecat.frames.frames import (
 )
 from pipecat.services.tts_service import TTSService
 from pipecat.tests.utils import SleepFrame, run_test
+from pipecat.utils.text.base_text_aggregator import AggregationType
 
 # ---------------------------------------------------------------------------
 # Test-only frame
@@ -422,7 +430,7 @@ def _assert_group_ordering(
         # All frames between TTSStartedFrame and TTSStoppedFrame must be audio.
         mid_types = types[started_idx + 1 : stopped_idx]
         for t in mid_types:
-            assert t is TTSAudioRawFrame, (
+            assert t in (TTSAudioRawFrame, TTSTextFrame), (
                 f"Group {foo_label!r}: unexpected frame {t.__name__!r} between "
                 f"TTSStartedFrame and TTSStoppedFrame. Got: {type_names}"
             )
@@ -551,7 +559,7 @@ async def test_http_push_text_llm_response_end_after_tts_text():
 
 @pytest.mark.asyncio
 async def test_http_word_timestamps_verbatim_tokens():
-    """HTTP path: text, PTS order, flag, and text-before-audio are all verified.
+    """HTTP path: text, PTS order, and text-before-audio are all verified.
 
     Word timestamps arrive in the audio context queue before the audio frame.
     _handle_audio_context caches them, then flushes when the first audio frame
@@ -572,7 +580,6 @@ async def test_http_word_timestamps_verbatim_tokens():
     audio_frames = [f for f in down if isinstance(f, TTSAudioRawFrame)]
 
     assert [f.text for f in tts_text_frames] == ["hello", "world"]
-    assert all(f.includes_inter_frame_spaces is True for f in tts_text_frames)
 
     pts_values = [f.pts for f in tts_text_frames]
     assert pts_values == sorted(pts_values) and len(set(pts_values)) == len(pts_values), (
@@ -590,15 +597,14 @@ async def test_http_word_timestamps_verbatim_tokens():
 
 @pytest.mark.asyncio
 async def test_http_word_timestamps_punctuation_tokens():
-    """Verbatim punctuation tokens are preserved with flag=True; default flag is False.
+    """Punct-only tokens are merged into the preceding word when includes_inter_frame_spaces=True.
 
-    Models the Inworld API scenario: the TTS returns tokens exactly as sent.
+    Models the Inworld API scenario: the TTS returns separate space and punctuation
-    Space placement rule:
+    tokens.  add_word_timestamps calls merge_punct_tokens when includes_inter_frame_spaces
-      - word-follows-word: space is the leading char of the next word (e.g. " world")
+    is True, collapsing those tokens into the preceding word before the tracker sees them.
-      - word-follows-punctuation: space is the trailing char of the punctuation token
+
-        (e.g. "! "), so the following word token carries no leading space.
+    With flag=False (default) tokens are forwarded as-is; the tracker strips leading/
-    The flag must reach every frame and the text must not be modified.
+    trailing whitespace from each frame word via get_word_for_frame().
-    Also acts as a regression guard that flag=False is the default.
     """
     verbatim_tokens = [
         ("hello", 0.0),
@@ -609,9 +615,9 @@ async def test_http_word_timestamps_punctuation_tokens():
         (" you", 0.75),
         ("?", 0.9),
     ]
-    expected_texts = ["hello", " world", "! ", "How", " are", " you", "?"]
 
-    # With flag=True: all tokens verbatim, all frames carry the flag.
+    # With flag=True: punct-only tokens ("! " and "?") are merged into the preceding
+    # words (" world" → " world! " and " you" → " you?"), then stripped by the tracker.
     tts_ifs = _MockWordTimestampHttpTTSService(
         includes_inter_frame_spaces=True,
         word_times=verbatim_tokens,
@@ -621,12 +627,11 @@ async def test_http_word_timestamps_punctuation_tokens():
         frames_to_send=[TTSSpeakFrame(text="hello world! How are you?", append_to_context=False)],
     )
     text_frames_ifs = [f for f in frames_ifs[0] if isinstance(f, TTSTextFrame)]
-    assert [f.text for f in text_frames_ifs] == expected_texts, (
+    assert [f.text for f in text_frames_ifs] == ["hello", "world!", "How", "are", "you?"], (
-        "Verbatim tokens must not be modified"
+        "Punct-only tokens must be merged into the preceding word"
     )
-    assert all(f.includes_inter_frame_spaces is True for f in text_frames_ifs)
 
-    # With flag=False (default): same tokens, flag must be False on every frame.
+    # With flag=False (default): no merging; tracker strips leading/trailing spaces.
     tts_plain = _MockWordTimestampHttpTTSService(
         word_times=verbatim_tokens,
     )
@@ -635,13 +640,12 @@ async def test_http_word_timestamps_punctuation_tokens():
         frames_to_send=[TTSSpeakFrame(text="hello world! How are you?", append_to_context=False)],
     )
     text_frames_plain = [f for f in frames_plain[0] if isinstance(f, TTSTextFrame)]
-    assert [f.text for f in text_frames_plain] == expected_texts
+    assert [f.text for f in text_frames_plain] == ["hello", "world", "!", "How", "are", "you", "?"]
-    assert all(f.includes_inter_frame_spaces is False for f in text_frames_plain)
 
 
 @pytest.mark.asyncio
 async def test_websocket_word_timestamps_verbatim_tokens():
-    """WebSocket path: _WordTimestampEntry carries verbatim text, PTS, and flag.
+    """WebSocket path: text, PTS order, and text-before-audio are all verified.
 
     Unlike the HTTP path the word timestamps are sent asynchronously from a
     background task.  They arrive before the audio frame and are cached until
@@ -662,7 +666,6 @@ async def test_websocket_word_timestamps_verbatim_tokens():
     audio_frames = [f for f in down if isinstance(f, TTSAudioRawFrame)]
 
     assert [f.text for f in tts_text_frames] == ["hello", "world"]
-    assert all(f.includes_inter_frame_spaces is True for f in tts_text_frames)
 
     pts_values = [f.pts for f in tts_text_frames]
     assert pts_values == sorted(pts_values) and len(set(pts_values)) == len(pts_values), (
@@ -678,7 +681,7 @@ async def test_websocket_word_timestamps_verbatim_tokens():
 
 @pytest.mark.asyncio
 async def test_websocket_word_timestamps_punctuation_tokens():
-    """WebSocket path: verbatim punctuation tokens reach TTSTextFrame unchanged."""
+    """WebSocket path: punct-only tokens are merged into the preceding word."""
     verbatim_tokens = [
         ("hello", 0.0),
         (" world", 0.15),
@@ -697,10 +700,443 @@ async def test_websocket_word_timestamps_punctuation_tokens():
         frames_to_send=[TTSSpeakFrame(text="hello world! How are you?", append_to_context=False)],
     )
     text_frames = [f for f in frames_received[0] if isinstance(f, TTSTextFrame)]
-    assert [f.text for f in text_frames] == ["hello", " world", "! ", "How", " are", " you", "?"], (
+    assert [f.text for f in text_frames] == ["hello", "world!", "How", "are", "you?"], (
-        "Verbatim tokens must not be modified"
+        "Punct-only tokens must be merged into the preceding word"
+    )
+
+
+# ---------------------------------------------------------------------------
+# Per-call word-timestamp mock (for overflow tests)
+# ---------------------------------------------------------------------------
+
+
+class _MockPerCallWordTimestampHttpTTSService(TTSService):
+    """HTTP-style TTS where each run_tts() call consumes its own word-time list.
+
+    Designed for tests that need different word tokens per sentence. The
+    ``word_times_per_call`` list is consumed in order; an empty inner list means
+    no word-timestamp events are emitted for that call.
+    """
+
+    def __init__(
+        self,
+        word_times_per_call: list[list[tuple[str, float]]],
+        **kwargs,
+    ):
+        super().__init__(
+            push_start_frame=True,
+            push_stop_frames=True,
+            push_text_frames=False,
+            sample_rate=_SAMPLE_RATE,
+            **kwargs,
+        )
+        self._word_times_queue = list(word_times_per_call)
+
+    def can_generate_metrics(self) -> bool:
+        return False
+
+    async def run_tts(self, text: str, context_id: str) -> AsyncGenerator[Frame, None]:
+        word_times = self._word_times_queue.pop(0) if self._word_times_queue else []
+        if word_times:
+            await self.add_word_timestamps(word_times, context_id=context_id)
+        yield TTSAudioRawFrame(
+            audio=_FAKE_AUDIO,
+            sample_rate=_SAMPLE_RATE,
+            num_channels=1,
+            context_id=context_id,
+        )
+
+
+# ---------------------------------------------------------------------------
+# Tests: skipped frame ordering (skip_aggregator_types)
+# ---------------------------------------------------------------------------
+
+
+@pytest.mark.asyncio
+async def test_http_skipped_frame_waits_for_spoken_words():
+    """Skipped frames are held until the preceding spoken slot's word timestamps
+    are all processed, then flushed in order (HTTP / synchronous audio path).
+
+    Sequence sent:
+        AggregatedTextFrame("hello world", SENTENCE)  — spoken; yields 2 TTSTextFrames
+        AggregatedTextFrame("some code", "code")       — in skip_aggregator_types; must wait
+
+    Expected downstream order:
+        TTSTextFrame("hello")
+        TTSTextFrame("world")
+        AggregatedTextFrame("some code", append_to_context=True)
+    """
+    tts = _MockWordTimestampHttpTTSService(skip_aggregator_types=["code"])
+    frames_received = await run_test(
+        tts,
+        frames_to_send=[
+            AggregatedTextFrame("hello world", AggregationType.SENTENCE),
+            AggregatedTextFrame("some code", "code"),
+        ],
+    )
+    down = frames_received[0]
+
+    word_frames = [f for f in down if isinstance(f, TTSTextFrame)]
+    skipped = [f for f in down if isinstance(f, AggregatedTextFrame) and f.text == "some code"]
+
+    assert [f.text for f in word_frames] == ["hello", "world"]
+    assert len(skipped) == 1
+    assert skipped[0].append_to_context is True
+
+    last_word_idx = max(down.index(f) for f in word_frames)
+    skipped_idx = down.index(skipped[0])
+    assert skipped_idx > last_word_idx, (
+        f"Skipped frame (pos {skipped_idx}) must appear after last word frame (pos {last_word_idx})"
+    )
+
+
+@pytest.mark.asyncio
+async def test_ws_skipped_frame_waits_for_spoken_words():
+    """Same ordering guarantee on the WebSocket / async audio delivery path.
+
+    Because audio is delivered from a background task after asyncio.sleep(), the
+    skipped frame arrives at _push_frame_respecting_previous_aggregated_frame
+    *before* the spoken slot's word timestamps have been processed, directly
+    exercising the hold-and-flush path.
+    """
+    tts = _MockWordTimestampWSTTSService(skip_aggregator_types=["code"])
+    frames_received = await run_test(
+        tts,
+        frames_to_send=[
+            AggregatedTextFrame("hello world", AggregationType.SENTENCE),
+            AggregatedTextFrame("some code", "code"),
+        ],
+    )
+    down = frames_received[0]
+
+    word_frames = [f for f in down if isinstance(f, TTSTextFrame)]
+    skipped = [f for f in down if isinstance(f, AggregatedTextFrame) and f.text == "some code"]
+
+    assert [f.text for f in word_frames] == ["hello", "world"]
+    assert len(skipped) == 1
+    assert skipped[0].append_to_context is True
+
+    last_word_idx = max(down.index(f) for f in word_frames)
+    skipped_idx = down.index(skipped[0])
+    assert skipped_idx > last_word_idx, (
+        f"Skipped frame (pos {skipped_idx}) must appear after last word frame (pos {last_word_idx})"
+    )
+
+
+@pytest.mark.asyncio
+async def test_skipped_frame_before_spoken_emits_immediately():
+    """A skipped frame with no preceding spoken slot is emitted right away.
+
+    Sequence:
+        AggregatedTextFrame("some code", "code")       — no spoken slot before it → emits now
+        AggregatedTextFrame("hello world", SENTENCE)   — spoken; TTSTextFrames follow
+
+    Expected: AggregatedTextFrame("some code") appears *before* TTSTextFrame("hello").
+    """
+    tts = _MockWordTimestampHttpTTSService(skip_aggregator_types=["code"])
+    frames_received = await run_test(
+        tts,
+        frames_to_send=[
+            AggregatedTextFrame("some code", "code"),
+            AggregatedTextFrame("hello world", AggregationType.SENTENCE),
+        ],
+    )
+    down = frames_received[0]
+
+    word_frames = [f for f in down if isinstance(f, TTSTextFrame)]
+    skipped = [f for f in down if isinstance(f, AggregatedTextFrame) and f.text == "some code"]
+
+    assert len(skipped) == 1
+    assert skipped[0].append_to_context is True
+    assert len(word_frames) >= 1
+
+    skipped_idx = down.index(skipped[0])
+    first_word_idx = down.index(word_frames[0])
+    assert skipped_idx < first_word_idx, (
+        f"Skipped frame (pos {skipped_idx}) must appear before first word frame (pos {first_word_idx})"
+    )
+
+
+@pytest.mark.asyncio
+async def test_skipped_frame_flushed_when_word_timestamps_incomplete():
+    """Force-complete path: skipped frame still emits when the TTS drops word timestamps.
+
+    Only one of the two expected tokens ("hello") is returned. The spoken slot never
+    reaches its expected character count through the normal path. When
+    on_audio_context_done fires it force-completes any remaining spoken slots and
+    flushes the waiting skipped frame.
+    """
+    tts = _MockWordTimestampHttpTTSService(
+        word_times=[("hello", 0.0)],  # "world" is never sent
+        skip_aggregator_types=["code"],
+    )
+    frames_received = await run_test(
+        tts,
+        frames_to_send=[
+            AggregatedTextFrame("hello world", AggregationType.SENTENCE),
+            AggregatedTextFrame("some code", "code"),
+        ],
+    )
+    down = frames_received[0]
+
+    skipped = [f for f in down if isinstance(f, AggregatedTextFrame) and f.text == "some code"]
+    assert len(skipped) == 1, "Skipped frame must be flushed via force-complete safety net"
+    assert skipped[0].append_to_context is True
+
+
+# ---------------------------------------------------------------------------
+# Tests: raw_text propagation through WordCompletionTracker
+# ---------------------------------------------------------------------------
+
+
+@pytest.mark.asyncio
+async def test_raw_text_propagated_to_tts_text_frames():
+    """raw_text on AggregatedTextFrame is split across TTSTextFrames by the tracker.
+
+    The frame carries raw_text="<card>4111 1111</card>" while the TTS-prepared
+    text is "4111 1111". The WordCompletionTracker advances a cursor through the
+    raw text in step with incoming word tokens, so each TTSTextFrame receives the
+    exact raw span it represents.
+
+    Expected (trailing whitespace stripped because includes_inter_frame_spaces=False):
+        TTSTextFrame("4111").raw_text == "<card>4111"
+        TTSTextFrame("1111").raw_text == "1111</card>"
+    """
+    tts = _MockWordTimestampHttpTTSService()
+    frames_received = await run_test(
+        tts,
+        frames_to_send=[
+            AggregatedTextFrame(
+                "4111 1111", AggregationType.SENTENCE, raw_text="<card>4111 1111</card>"
+            )
+        ],
+    )
+    word_frames = [f for f in frames_received[0] if isinstance(f, TTSTextFrame)]
+
+    assert [f.text for f in word_frames] == ["4111", "1111"]
+    # get_raw_consumed() strips trailing whitespace when includes_inter_frame_spaces=False
+    assert word_frames[0].raw_text == "<card>4111"
+    assert word_frames[1].raw_text == "1111</card>"
+
+
+# ---------------------------------------------------------------------------
+# Tests: overflow — TTS word spanning two AggregatedTextFrame boundaries
+# ---------------------------------------------------------------------------
+
+
+@pytest.mark.asyncio
+async def test_overflow_word_spanning_two_aggregated_frames():
+    """A single TTS token straddling two AggregatedTextFrame boundaries produces
+    two correctly-attributed TTSTextFrames.
+
+    Setup:
+        Frame 1: AggregatedTextFrame("abc", SENTENCE)
+        Frame 2: AggregatedTextFrame("def", SENTENCE)
+
+    The TTS for frame 1 returns the single token "abcdef", which overshoots
+    frame 1 by three characters. _emit_overflow_word splits it:
+        TTSTextFrame("abc")  — frame 1's portion (context_id = ctx1)
+        TTSTextFrame("def")  — overflow attributed to frame 2 (context_id = ctx2)
+
+    Frame 2 receives no word-timestamp events because the overflow already
+    consumed its expected text.
+    """
+    tts = _MockPerCallWordTimestampHttpTTSService(
+        word_times_per_call=[
+            [("abcdef", 0.0)],  # frame 1: single token spanning both frames
+            [],  # frame 2: no word timestamps (overflow already covered it)
+        ]
+    )
+    frames_received = await run_test(
+        tts,
+        frames_to_send=[
+            AggregatedTextFrame("abc", AggregationType.SENTENCE),
+            AggregatedTextFrame("def", AggregationType.SENTENCE),
+        ],
+    )
+    word_frames = [f for f in frames_received[0] if isinstance(f, TTSTextFrame)]
+
+    assert [f.text for f in word_frames] == ["abc", "def"], (
+        f"Expected ['abc', 'def'] but got {[f.text for f in word_frames]}"
+    )
+    assert word_frames[0].context_id != word_frames[1].context_id, (
+        "Overflow TTSTextFrame must carry frame 2's context_id, not frame 1's"
+    )
+
+
+# ---------------------------------------------------------------------------
+# Per-call word-timestamp mock for WebSocket path (for force-complete tests)
+# ---------------------------------------------------------------------------
+
+
+class _MockPerCallWordTimestampWSTTSService(TTSService):
+    """WebSocket-style TTS where each run_tts() call consumes its own word-time list.
+
+    Mirrors _MockPerCallWordTimestampHttpTTSService but uses the async audio-context
+    delivery pattern so it exercises _handle_audio_context (the WebSocket path).
+    An empty inner list means no word-timestamp events are emitted for that call.
+    """
+
+    def __init__(
+        self,
+        word_times_per_call: list[list[tuple[str, float]]],
+        **kwargs,
+    ):
+        super().__init__(
+            push_start_frame=True,
+            push_text_frames=False,
+            pause_frame_processing=False,
+            sample_rate=_SAMPLE_RATE,
+            **kwargs,
+        )
+        self._word_times_queue = list(word_times_per_call)
+
+    def can_generate_metrics(self) -> bool:
+        return False
+
+    async def run_tts(self, text: str, context_id: str) -> AsyncGenerator[Frame, None]:
+        word_times = self._word_times_queue.pop(0) if self._word_times_queue else []
+
+        async def _deliver():
+            await asyncio.sleep(0.01)
+            if word_times:
+                await self.add_word_timestamps(word_times, context_id=context_id)
+            await self.append_to_audio_context(
+                context_id,
+                TTSAudioRawFrame(
+                    audio=_FAKE_AUDIO,
+                    sample_rate=_SAMPLE_RATE,
+                    num_channels=1,
+                    context_id=context_id,
+                ),
+            )
+            await self.append_to_audio_context(context_id, TTSStoppedFrame(context_id=context_id))
+            await self.remove_audio_context(context_id)
+
+        self.create_task(_deliver(), name=f"mock_ws_per_call_deliver_{context_id}")
+        if False:
+            yield
+
+
+# ---------------------------------------------------------------------------
+# Tests: _force_complete_spoken_slots — TTSTextFrame emission for dropped timestamps
+# ---------------------------------------------------------------------------
+
+
+@pytest.mark.asyncio
+async def test_http_force_complete_partial_timestamps_emits_remaining_text():
+    """_force_complete_spoken_slots emits a TTSTextFrame for the unspoken word suffix.
+
+    Only the first token ("hello") is delivered as a word-timestamp event; "world"
+    is never sent.  When the audio context ends _force_complete_spoken_slots fires,
+    reads get_remaining_text() from the tracker, and emits TTSTextFrame("world").
+
+    Expected TTSTextFrames in order: ["hello", "world"].
+    """
+    tts = _MockWordTimestampHttpTTSService(word_times=[("hello", 0.0)])
+    frames_received = await run_test(
+        tts,
+        frames_to_send=[TTSSpeakFrame(text="hello world", append_to_context=False)],
+    )
+    word_frames = [f for f in frames_received[0] if isinstance(f, TTSTextFrame)]
+
+    assert [f.text for f in word_frames] == ["hello", "world"], (
+        f"Expected ['hello', 'world'] but got {[f.text for f in word_frames]}"
+    )
+
+
+@pytest.mark.asyncio
+async def test_http_force_complete_no_timestamps_emits_full_text():
+    """_force_complete_spoken_slots emits the full text when no word timestamps arrive.
+
+    No word-timestamp events are sent for "hello world".  The slot remains incomplete
+    when the audio context ends; force-complete reads the full remaining text from the
+    tracker and emits TTSTextFrame("hello world").
+    """
+    tts = _MockPerCallWordTimestampHttpTTSService(word_times_per_call=[[]])
+    frames_received = await run_test(
+        tts,
+        frames_to_send=[TTSSpeakFrame(text="hello world", append_to_context=False)],
+    )
+    word_frames = [f for f in frames_received[0] if isinstance(f, TTSTextFrame)]
+
+    assert len(word_frames) == 1, (
+        f"Expected exactly 1 TTSTextFrame, got {len(word_frames)}: {[f.text for f in word_frames]}"
+    )
+    assert word_frames[0].text == "hello world", (
+        f"Expected TTSTextFrame('hello world'), got {word_frames[0].text!r}"
+    )
+
+
+@pytest.mark.asyncio
+async def test_http_force_complete_raw_text_propagated():
+    """force-complete carries the correct raw_text span on the emitted TTSTextFrame.
+
+    AggregatedTextFrame carries raw_text="<card>4111 1111</card>".  Only "4111" arrives
+    as a word-timestamp; "1111" is force-completed.
+
+    Expected:
+        TTSTextFrame("4111").raw_text == "<card>4111"    — from normal word path
+        TTSTextFrame("1111").raw_text == "1111</card>"   — from force-complete path
+    """
+    tts = _MockPerCallWordTimestampHttpTTSService(word_times_per_call=[[("4111", 0.0)]])
+    frames_received = await run_test(
+        tts,
+        frames_to_send=[
+            AggregatedTextFrame(
+                "4111 1111", AggregationType.SENTENCE, raw_text="<card>4111 1111</card>"
+            )
+        ],
+    )
+    word_frames = [f for f in frames_received[0] if isinstance(f, TTSTextFrame)]
+
+    assert [f.text for f in word_frames] == ["4111", "1111"], (
+        f"Expected ['4111', '1111'] but got {[f.text for f in word_frames]}"
+    )
+    assert word_frames[0].raw_text == "<card>4111", (
+        f"Expected raw_text '<card>4111' on first frame, got {word_frames[0].raw_text!r}"
+    )
+    assert word_frames[1].raw_text == "1111</card>", (
+        f"Expected raw_text '1111</card>' on force-complete frame, got {word_frames[1].raw_text!r}"
+    )
+
+
+@pytest.mark.asyncio
+async def test_ws_force_complete_partial_timestamps_emits_remaining_text():
+    """WebSocket path: _force_complete_spoken_slots emits TTSTextFrame for dropped token.
+
+    Mirrors test_http_force_complete_partial_timestamps_emits_remaining_text on the
+    async audio delivery path to confirm force-complete fires correctly from
+    _handle_audio_context when TTSStoppedFrame arrives before all word timestamps.
+    """
+    tts = _MockWordTimestampWSTTSService(word_times=[("hello", 0.0)])
+    frames_received = await run_test(
+        tts,
+        frames_to_send=[TTSSpeakFrame(text="hello world", append_to_context=False)],
+    )
+    word_frames = [f for f in frames_received[0] if isinstance(f, TTSTextFrame)]
+
+    assert [f.text for f in word_frames] == ["hello", "world"], (
+        f"Expected ['hello', 'world'] but got {[f.text for f in word_frames]}"
+    )
+
+
+@pytest.mark.asyncio
+async def test_ws_force_complete_no_timestamps_emits_full_text():
+    """WebSocket path: full text emitted as single TTSTextFrame when no timestamps arrive."""
+    tts = _MockPerCallWordTimestampWSTTSService(word_times_per_call=[[]])
+    frames_received = await run_test(
+        tts,
+        frames_to_send=[TTSSpeakFrame(text="hello world", append_to_context=False)],
+    )
+    word_frames = [f for f in frames_received[0] if isinstance(f, TTSTextFrame)]
+
+    assert len(word_frames) == 1, (
+        f"Expected exactly 1 TTSTextFrame, got {len(word_frames)}: {[f.text for f in word_frames]}"
+    )
+    assert word_frames[0].text == "hello world", (
+        f"Expected TTSTextFrame('hello world'), got {word_frames[0].text!r}"
     )
-    assert all(f.includes_inter_frame_spaces is True for f in text_frames)
 
 
 @pytest.mark.asyncio

tests/test_word_timestamp_utils.py

@@ -0,0 +1,90 @@
+#
+# Copyright (c) 2024-2026, Daily
+#
+# SPDX-License-Identifier: BSD 2-Clause License
+#
+
+import unittest
+
+from pipecat.utils.text.word_timestamp_utils import merge_punct_tokens
+
+
+class TestMergePunctTokens(unittest.TestCase):
+    def test_empty_list(self):
+        self.assertEqual(merge_punct_tokens([]), [])
+
+    def test_all_alnum_words_pass_through(self):
+        input = [("hello", 0.0), ("world", 1.0)]
+        self.assertEqual(merge_punct_tokens(input), [("hello", 0.0), ("world", 1.0)])
+
+    def test_trailing_space_merged_and_stripped(self):
+        input = [("I", 0.0), (" ", 0.2)]
+        self.assertEqual(merge_punct_tokens(input), [("I", 0.0)])
+
+    def test_comma_space_merged_and_stripped(self):
+        input = [("questions", 1.0), (", ", 1.2), ("explain", 1.4)]
+        self.assertEqual(merge_punct_tokens(input), [("questions,", 1.0), ("explain", 1.4)])
+
+    def test_leading_space_with_no_preceding_word_discarded(self):
+        input = [(" ", 0.0), ("hello", 0.5)]
+        self.assertEqual(merge_punct_tokens(input), [("hello", 0.5)])
+
+    def test_leading_empty_string_discarded(self):
+        input = [("", 0.0), ("hello", 0.5)]
+        self.assertEqual(merge_punct_tokens(input), [("hello", 0.5)])
+
+    def test_multiple_consecutive_punct_tokens_merged_and_stripped(self):
+        input = [("word", 0.0), (",", 0.1), (" ", 0.2), ("next", 0.3)]
+        self.assertEqual(merge_punct_tokens(input), [("word,", 0.0), ("next", 0.3)])
+
+    def test_timestamp_of_preceding_word_is_kept(self):
+        """Merged punct tokens adopt the preceding word's timestamp."""
+        input = [("hello", 2.5), (",", 2.7)]
+        result = merge_punct_tokens(input)
+        self.assertEqual(result, [("hello,", 2.5)])
+
+    def test_xml_tag_only_token_is_treated_as_punct(self):
+        """A token that is only an XML tag (no alnum chars) merges into the preceding word."""
+        input = [("word", 0.0), ("<break/>", 0.1), ("next", 0.3)]
+        self.assertEqual(merge_punct_tokens(input), [("word<break/>", 0.0), ("next", 0.3)])
+
+    def test_xml_tag_with_alnum_content_passes_through(self):
+        """A token like '<spell>123</spell>' has alnum chars after stripping tags."""
+        input = [("<spell>123</spell>", 0.0), ("and", 0.5)]
+        self.assertEqual(merge_punct_tokens(input), [("<spell>123</spell>", 0.0), ("and", 0.5)])
+
+    def test_inworld_style_full_stream(self):
+        """Full Inworld-style raw stream produces expected merged and stripped output."""
+        raw = [
+            ("", 0.0),
+            ("I", 0.1),
+            (" ", 0.2),
+            ("can", 0.3),
+            (" ", 0.4),
+            ("answer", 0.5),
+            (" ", 0.6),
+            ("questions", 0.7),
+            (", ", 0.8),
+            ("explain", 0.9),
+            (" ", 1.0),
+            ("things", 1.1),
+            (".", 1.2),
+        ]
+        expected = [
+            ("I", 0.1),
+            ("can", 0.3),
+            ("answer", 0.5),
+            ("questions,", 0.7),
+            ("explain", 0.9),
+            ("things.", 1.1),
+        ]
+        self.assertEqual(merge_punct_tokens(raw), expected)
+
+    def test_only_punct_tokens_returns_empty(self):
+        """A list containing only punct/space tokens produces an empty result."""
+        input = [(" ", 0.0), (",", 0.1), (".", 0.2)]
+        self.assertEqual(merge_punct_tokens(input), [])
+
+
+if __name__ == "__main__":
+    unittest.main()