diff --git a/CHANGELOG.md b/CHANGELOG.md
index e01359589..b83d77d54 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -74,6 +74,10 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 - Removed `SileroVAD` frame processor, just use `SileroVADAnalyzer`
   instead. Also removed, `07a-interruptible-vad.py` example.
 
+### Fixed
+
+- Fixed an issue with `CartesiaTTSService` where `TTSTextFrame` messages weren't being emitted when the model was set to `sonic`. This resulted in the assistant context not being updated with assistant messages.
+
 ### Other
 
 - Added foundation example `07y-minimax-http.py` to show how to use the
diff --git a/src/pipecat/services/cartesia/tts.py b/src/pipecat/services/cartesia/tts.py
index 3a7d6c696..bc7b1f121 100644
--- a/src/pipecat/services/cartesia/tts.py
+++ b/src/pipecat/services/cartesia/tts.py
@@ -167,7 +167,7 @@ class CartesiaTTSService(AudioContextWordTTSService):
             "output_format": self._settings["output_format"],
             "language": self._settings["language"],
             "add_timestamps": add_timestamps,
-            "use_original_timestamps": True,
+            "use_original_timestamps": False if self.model_name == "sonic" else True,
         }
         return json.dumps(msg)