diff --git a/CHANGELOG.md b/CHANGELOG.md
index 5c6ff6143..2689d1f3f 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -80,6 +80,10 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 ### Changed
 
+- Improved `concatenate_aggregated_text()` to one word outputs from OpenAI
+  Realtime and Gemini Live. Text fragments are now correctly concatenated
+  without spaces when these patterns are detected.
+
 - `STTMuteFilter` no longer sends `STTMuteFrame` to the STT service. The filter
   now blocks frames locally without instructing the STT service to stop
   processing audio. This prevents inactivity-related errors (such as 409 errors
diff --git a/tests/test_transcript_processor.py b/tests/test_transcript_processor.py
index b433951ce..d45d5ba3b 100644
--- a/tests/test_transcript_processor.py
+++ b/tests/test_transcript_processor.py
@@ -479,3 +479,103 @@ class TestUserTranscriptProcessor(unittest.IsolatedAsyncioTestCase):
         self.assertEqual(message.role, "assistant")
         # Should be properly joined without extra spaces
         self.assertEqual(message.content, "Hello there! How's it going?")
+
+    async def test_openai_realtime_syllable_fragments(self):
+        """Test OpenAI Realtime syllable-by-syllable output with standalone punctuation
+
+        OpenAI Realtime can output single words as syllable fragments with punctuation
+        as a separate fragment. Example: ["Met", "am", "orph", "osis", "."]
+        This should be concatenated without spaces to form "Metamorphosis."
+        """
+        processor = AssistantTranscriptProcessor()
+
+        received_updates = []
+
+        @processor.event_handler("on_transcript_update")
+        async def handle_update(proc, frame: TranscriptionUpdateFrame):
+            received_updates.append(frame)
+
+        # Simulate OpenAI Realtime syllable-by-syllable output
+        frames_to_send = [
+            BotStartedSpeakingFrame(),
+            SleepFrame(),
+            TTSTextFrame(text="Met"),
+            TTSTextFrame(text="am"),
+            TTSTextFrame(text="orph"),
+            TTSTextFrame(text="osis"),
+            TTSTextFrame(text="."),  # Standalone punctuation fragment
+            BotStoppedSpeakingFrame(),
+        ]
+
+        expected_down_frames = [
+            BotStartedSpeakingFrame,
+            BotStoppedSpeakingFrame,
+            TTSTextFrame,
+            TTSTextFrame,
+            TTSTextFrame,
+            TTSTextFrame,
+            TTSTextFrame,
+            TranscriptionUpdateFrame,
+        ]
+
+        await run_test(
+            processor,
+            frames_to_send=frames_to_send,
+            expected_down_frames=expected_down_frames,
+        )
+
+        # Verify syllables are concatenated without spaces
+        self.assertEqual(len(received_updates), 1)
+        message = received_updates[0].messages[0]
+        self.assertEqual(message.role, "assistant")
+        self.assertEqual(message.content, "Metamorphosis.")
+
+    async def test_gemini_live_syllable_fragments_with_newline(self):
+        """Test Gemini Live syllable-by-syllable output with trailing newline
+
+        Gemini Live can output syllable fragments where the last fragment contains
+        trailing whitespace like newlines. Example: ["Met", "amo", "rph", "osi", "s.\\n"]
+        This should be concatenated without spaces to form "Metamorphosis."
+        """
+        processor = AssistantTranscriptProcessor()
+
+        received_updates = []
+
+        @processor.event_handler("on_transcript_update")
+        async def handle_update(proc, frame: TranscriptionUpdateFrame):
+            received_updates.append(frame)
+
+        # Simulate Gemini Live syllable-by-syllable output with trailing newline
+        frames_to_send = [
+            BotStartedSpeakingFrame(),
+            SleepFrame(),
+            TTSTextFrame(text="Met"),
+            TTSTextFrame(text="amo"),
+            TTSTextFrame(text="rph"),
+            TTSTextFrame(text="osi"),
+            TTSTextFrame(text="s.\n"),  # Last fragment with trailing newline
+            BotStoppedSpeakingFrame(),
+        ]
+
+        expected_down_frames = [
+            BotStartedSpeakingFrame,
+            BotStoppedSpeakingFrame,
+            TTSTextFrame,
+            TTSTextFrame,
+            TTSTextFrame,
+            TTSTextFrame,
+            TTSTextFrame,
+            TranscriptionUpdateFrame,
+        ]
+
+        await run_test(
+            processor,
+            frames_to_send=frames_to_send,
+            expected_down_frames=expected_down_frames,
+        )
+
+        # Verify syllables are concatenated without spaces and newline is stripped
+        self.assertEqual(len(received_updates), 1)
+        message = received_updates[0].messages[0]
+        self.assertEqual(message.role, "assistant")
+        self.assertEqual(message.content, "Metamorphosis.")