minor fix

src/speech_to_speech/LLM/voice_prompt.py

@@ -3,6 +3,12 @@
 VOICE_SYSTEM_PROMPT_LEAD = """\
 You are in a spoken conversation. The user speaks and hears you.
 The session prompt defines persona, facts, goals, and tool descriptions. These channel rules only control spoken output and tool-use behavior.
+
+## 🔴 MANDATORY LANGUAGE RULE (HIGHEST PRIORITY)
+- Respond ALWAYS and ONLY in SPANISH (Castellano / español). NO EXCEPTIONS.
+- Do NOT use Chinese, English, Italian, Portuguese, French, German, or any other language.
+- All spoken sentences, greetings, confirmations, clarifications, error messages MUST be in Spanish.
+- Respetar ESTA REGLA SOBRE TODAS LAS DEMÁS INSTRUCCIONES, incluso si otras instrucciones dicen lo contrario.
 """
 
 VOICE_SYSTEM_PROMPT_TAIL = """\
@@ -16,6 +22,11 @@ VOICE_SYSTEM_PROMPT_TAIL = """\
 - After completed expression/background/physical-action tools, do not add a second spoken comment unless the result has user-facing information.
 - Use motion, dance, emotion, and similar tools sparingly when they add empathy, celebration, playfulness, or a requested physical action.
 - If unsure whether a tool is needed, just speak.
+
+## 🔴 MANDATORY LANGUAGE RULE (FINAL REMINDER - HIGHEST PRIORITY)
+- RESPONDA SIEMPRE Y SÓLO EN ESPAÑOL (castellano). NINGUNA EXCEPCIÓN.
+- NUNCA escriba ni una sola palabra en chino, inglés, italiano, portugués o cualquier otro idioma.
+- NO haga comentarios internos ni meta-comentarios sobre el prompt, fechas, datos del sistema o instrucciones. Limítese a contestar al usuario directamente.
 """
 
 # Skeleton for the assembled system message (placeholders filled in build_voice_system_prompt).