fix: AzureTTSService punctuation spacing

src/pipecat/services/azure/tts.py

@@ -277,6 +277,8 @@ class AzureTTSService(WordTTSService, AzureBaseTTSService):
         self._started = False
         self._first_chunk = True
         self._cumulative_audio_offset: float = 0.0  # Cumulative audio duration in seconds
+        self._last_word: Optional[str] = None  # Track last word for punctuation merging
+        self._last_timestamp: Optional[float] = None  # Track last timestamp
 
     def can_generate_metrics(self) -> bool:
         """Check if this service can generate processing metrics.
@@ -346,9 +348,24 @@ class AzureTTSService(WordTTSService, AzureBaseTTSService):
         await self.cancel_task(self._word_processor_task)
         self._word_processor_task = None
 
+    def _is_punctuation_only(self, text: str) -> bool:
+        """Check if text consists only of punctuation and whitespace.
+
+        Args:
+            text: Text to check.
+
+        Returns:
+            True if text is only punctuation/whitespace, False otherwise.
+        """
+        return text and all(not c.isalnum() for c in text)
+
     def _handle_word_boundary(self, evt):
         """Handle word boundary events from Azure SDK.
 
+        Azure sends punctuation as separate word boundaries, which causes
+        spacing issues in the final transcript. This method merges punctuation
+        with the previous word to maintain proper formatting.
+
         Args:
             evt: SpeechSynthesisWordBoundaryEventArgs from Azure Speech SDK
                 containing word text and audio offset timing.
@@ -362,13 +379,23 @@ class AzureTTSService(WordTTSService, AzureBaseTTSService):
         # Add cumulative offset to get absolute timestamp across sentences
         absolute_seconds = self._cumulative_audio_offset + sentence_relative_seconds
 
-        # Queue word timestamp for async processing
-        # Use thread-safe queue since this is called from Azure SDK thread
-        if word:
-            logger.trace(f"{self}: Word boundary - '{word}' at {absolute_seconds:.2f}s")
-            # Put in temporary queue - will be processed by async task
-            # Store as (word, timestamp_in_seconds) tuple
-            self._word_boundary_queue.put_nowait((word, absolute_seconds))
+        if not word:
+            return
+
+        # Check if this is punctuation-only
+        is_punctuation = self._is_punctuation_only(word)
+
+        if is_punctuation and self._last_word is not None:
+            # Merge punctuation with the previous word (don't queue yet, more punctuation might follow)
+            self._last_word += word
+        else:
+            # This is a real word. First, queue any pending word from before.
+            if self._last_word is not None:
+                self._word_boundary_queue.put_nowait((self._last_word, self._last_timestamp))
+
+            # Now store this new word for next time
+            self._last_word = word
+            self._last_timestamp = absolute_seconds
 
     async def _word_processor_task_handler(self):
         """Process word timestamps from the queue and call add_word_timestamps."""
@@ -397,6 +424,12 @@ class AzureTTSService(WordTTSService, AzureBaseTTSService):
         Args:
             evt: Completion event from Azure Speech SDK.
         """
+        # Flush any pending word before completing
+        if self._last_word is not None:
+            self._word_boundary_queue.put_nowait((self._last_word, self._last_timestamp))
+            self._last_word = None
+            self._last_timestamp = None
+
         # Update cumulative audio offset for next sentence
         if evt.result and evt.result.audio_duration:
             self._cumulative_audio_offset += evt.result.audio_duration.total_seconds()
@@ -435,6 +468,8 @@ class AzureTTSService(WordTTSService, AzureBaseTTSService):
         self._started = False
         self._first_chunk = True
         self._cumulative_audio_offset = 0.0
+        self._last_word = None
+        self._last_timestamp = None
 
     async def flush_audio(self):
         """Flush any pending audio data."""