diff --git a/app/helpers/call_events.py b/app/helpers/call_events.py
index c154039c..6076dbfc 100644
--- a/app/helpers/call_events.py
+++ b/app/helpers/call_events.py
@@ -469,7 +469,7 @@ async def on_ivr_recognized(
         call=call,
         scheduler=scheduler,
     ):
-        call.lang = lang.short_code
+        call.lang_short_code = lang.short_code
         call.recognition_retry = 0
 
     await start_audio_streaming(
@@ -528,6 +528,7 @@ async def on_sms_received(
             MessageModel(
                 action=MessageActionEnum.SMS,
                 content=message,
+                lang_short_code=call.lang.short_code,
                 persona=MessagePersonaEnum.HUMAN,
             )
         )
@@ -655,6 +656,7 @@ def _validate(req: str | None) -> tuple[bool, str | None, str | None]:
             call=call,
             scheduler=scheduler,
         ):
+            # Dont't store the lang as we aren't sure about the language of the SMS
             call.messages.append(
                 MessageModel(
                     action=MessageActionEnum.SMS,
diff --git a/app/helpers/call_llm.py b/app/helpers/call_llm.py
index 0f4bbecb..07e36eea 100644
--- a/app/helpers/call_llm.py
+++ b/app/helpers/call_llm.py
@@ -196,6 +196,7 @@ async def _response_callback(_retry: bool = False) -> None:
                 call.messages.append(
                     MessageModel(
                         content=stt_text,
+                        lang_short_code=call.lang.short_code,
                         persona=MessagePersonaEnum.HUMAN,
                     )
                 )
@@ -491,6 +492,13 @@ async def _content_callback(buffer: str) -> None:
         tools = await plugins.to_openai(frozenset(tool_blacklist))
         # logger.debug("Tools: %s", tools)
 
+    # Translate messages to avoid LLM hallucinations
+    # See: https://github.com/microsoft/call-center-ai/issues/260
+    translated_messages = await asyncio.gather(
+        *[message.translate(call.lang.short_code) for message in call.messages]
+    )
+    logger.debug("Translated messages: %s", translated_messages)
+
     # Execute LLM inference
     content_buffer_pointer = 0
     last_buffered_tool_id = None
@@ -500,7 +508,7 @@ async def _content_callback(buffer: str) -> None:
         # Consume the completion stream
         async for delta in completion_stream(
             max_tokens=160,  # Lowest possible value for 90% of the cases, if not sufficient, retry will be triggered, 100 tokens ~= 75 words, 20 words ~= 1 sentence, 6 sentences ~= 160 tokens
-            messages=call.messages,
+            messages=translated_messages,
             system=system,
             tools=tools,
         ):
diff --git a/app/helpers/call_utils.py b/app/helpers/call_utils.py
index 1eed49f3..87b06673 100644
--- a/app/helpers/call_utils.py
+++ b/app/helpers/call_utils.py
@@ -309,6 +309,7 @@ async def _store_assistant_message(
         call.messages.append(
             MessageModel(
                 content=text,
+                lang_short_code=call.lang.short_code,
                 persona=MessagePersonaEnum.ASSISTANT,
                 style=style,
             )
diff --git a/app/helpers/llm_tools.py b/app/helpers/llm_tools.py
index 8a1dd0a8..08bbf61c 100644
--- a/app/helpers/llm_tools.py
+++ b/app/helpers/llm_tools.py
@@ -427,6 +427,7 @@ async def send_sms(
             MessageModel(
                 action=MessageActionEnum.SMS,
                 content=message,
+                lang_short_code=self.call.lang.short_code,
                 persona=MessagePersonaEnum.ASSISTANT,
             )
         )
@@ -519,7 +520,7 @@ async def speech_lang(
 
         # Update lang
         initial_lang = self.call.lang.short_code
-        self.call.lang = lang
+        self.call.lang_short_code = lang
 
         # LLM confirmation
         return f"Voice language set to {lang} (was {initial_lang})"
diff --git a/app/helpers/translation.py b/app/helpers/translation.py
index 260af052..9a3f33b8 100644
--- a/app/helpers/translation.py
+++ b/app/helpers/translation.py
@@ -29,7 +29,7 @@ async def translate_text(text: str, source_lang: str, target_lang: str) -> str |
     """
     Translate text from source language to target language.
 
-    Catch errors for a maximum of 3 times.
+    If the source and target languages are the same, the original text is returned. Catch errors for a maximum of 3 times.
     """
     # No need to translate
     if source_lang == target_lang:
diff --git a/app/models/call.py b/app/models/call.py
index 182c6bfe..c34c9945 100644
--- a/app/models/call.py
+++ b/app/models/call.py
@@ -120,10 +120,6 @@ def lang(self) -> LanguageEntryModel:  # pyright: ignore
             )
         return default
 
-    @lang.setter
-    def lang(self, short_code: str) -> None:
-        self.lang_short_code = short_code
-
     async def trainings(self, cache_only: bool = True) -> list[TrainingModel]:
         """
         Get the trainings from the last messages.
diff --git a/app/models/message.py b/app/models/message.py
index c2fc1084..c1f682c7 100644
--- a/app/models/message.py
+++ b/app/models/message.py
@@ -115,10 +115,38 @@ class MessageModel(BaseModel):
     # Editable fields
     action: ActionEnum = ActionEnum.TALK
     content: str
+    lang_short_code: str | None = None
     persona: PersonaEnum
     style: StyleEnum = StyleEnum.NONE
     tool_calls: list[ToolModel] = []
 
+    async def translate(self, target_short_code: str) -> "MessageModel":
+        """
+        Translate the message to a target language.
+
+        A copy of the model is returned with the translated content.
+        """
+        from app.helpers.translation import translate_text
+
+        # Work on a copy to avoid modifying the original model in the database
+        copy = self.model_copy()
+
+        # Skip if no language is set
+        if not self.lang_short_code:
+            return copy
+
+        # Apply translation
+        translation = await translate_text(
+            source_lang=self.lang_short_code,
+            target_lang=target_short_code,
+            text=self.content,
+        )
+        if translation:
+            copy.content = translation
+            copy.lang_short_code = target_short_code
+
+        return copy
+
     @field_validator("created_at")
     @classmethod
     def _validate_created_at(cls, created_at: datetime) -> datetime:
diff --git a/tests/llm.py b/tests/llm.py
index 0dc17c26..89644a21 100644
--- a/tests/llm.py
+++ b/tests/llm.py
@@ -274,7 +274,7 @@ def _play_media_callback(text: str) -> None:
     call_client = automation_client.get_call_connection()
 
     # Mock call
-    call.lang = lang
+    call.lang_short_code = lang
 
     async with Scheduler() as scheduler:
 
@@ -312,6 +312,7 @@ async def _training_callback(_call: CallStateModel) -> None:
                 call.messages.append(
                     MessageModel(
                         content=speech,
+                        lang_short_code=call.lang.short_code,
                         persona=MessagePersonaEnum.HUMAN,
                     )
                 )
diff --git a/tests/local.py b/tests/local.py
index 90fe63a1..fac8a180 100644
--- a/tests/local.py
+++ b/tests/local.py
@@ -95,6 +95,7 @@ async def _training_callback(_call: CallStateModel) -> None:
                 call.messages.append(
                     MessageModel(
                         content=speech,
+                        lang_short_code=call.lang.short_code,
                         persona=MessagePersonaEnum.HUMAN,
                     )
                 )
diff --git a/tests/search.py b/tests/search.py
index 57867d2c..907b8d2e 100644
--- a/tests/search.py
+++ b/tests/search.py
@@ -139,13 +139,14 @@ async def test_relevancy(  # noqa: PLR0913
     Test is repeated 10 times to catch multi-threading and concurrency issues.
     """
     # Set call language
-    call.lang = lang
+    call.lang_short_code = lang
 
     # Fill call with messages
     for speech in speeches:
         call.messages.append(
             MessageModel(
                 content=speech,
+                lang_short_code=call.lang.short_code,
                 persona=MessagePersonaEnum.HUMAN,
             )
         )