services: allow TTSModelUpdateFrame to also update language and voice

src/pipecat/frames/frames.py

@@ -441,6 +441,8 @@ class TTSModelUpdateFrame(ControlFrame):
     """A control frame containing a request to update the TTS model.
     """
     model: str
+    voice: str | None = None
+    language: Language | None = None
 
 
 @dataclass

src/pipecat/services/ai_services.py

@@ -179,7 +179,7 @@ class TTSService(AIService):
         self._current_sentence: str = ""
 
     @abstractmethod
-    async def set_model(self, model: str):
+    async def set_model(self, model: str, voice: str | None, language: Language | None):
         pass
 
     @abstractmethod

src/pipecat/services/cartesia.py

@@ -110,9 +110,16 @@ class CartesiaTTSService(TTSService):
     def can_generate_metrics(self) -> bool:
         return True
 
-    async def set_model(self, model: str):
+    async def set_model(self, model: str, voice: str | None, language: Language | None):
         logger.debug(f"Switching TTS model to: [{model}]")
         self._model_id = model
+        if language:
+            logger.debug(f"Switching TTS language to: [{language}]")
+            cartesia_language = language_to_cartesia_language(language)
+            self._language = cartesia_language
+        if voice:
+            logger.debug(f"Switching TTS voice to: [{voice}]")
+            self._voice_id = voice
 
     async def set_voice(self, voice: str):
         logger.debug(f"Switching TTS voice to: [{voice}]")