diff --git a/python/rtclient/models.py b/python/rtclient/models.py
index 1a927cd..01c9508 100644
--- a/python/rtclient/models.py
+++ b/python/rtclient/models.py
@@ -45,6 +45,7 @@ class FunctionToolChoice(ModelWithDefaults):
 
 class InputAudioTranscription(BaseModel):
     model: Literal["whisper-1"]
+    language: Optional[str]
 
 
 class ClientMessageBase(ModelWithDefaults):