use ISO 639-1 language code

common/arg.cpp

@@ -4229,7 +4229,7 @@ common_params_context common_params_parser_init(common_params & params, llama_ex
 
     add_opt(common_arg(
         {"--tts-lang"}, "FNAME",
-        "language (two-letter country code) for audio generation\n"
+        "language (ISO 639-1) for audio generation\n"
         "see tts/README.md for per-model usage notes",
         [](common_params & params, const std::string & value) {
             params.tts_lang = value;

tools/mtmd/mtmd-helper-gen.cpp

@@ -19,15 +19,18 @@
 // Audio generation helpers
 //
 
-// maps the 2-letter --tts-lang codes (see tools/tts/README.md) to the language
+// maps the --tts-lang codes (see tools/tts/README.md) to the language
 // names used by the codec_language special tokens
+//
+// primary keys are ISO 639-1 codes; the old non-standard codes ("cn", "ge",
+// "po", "sp") are kept as aliases for backward compatibility
 static const std::unordered_map<std::string, std::string> tts_lang_codes = {
-    { "cn", "chinese"    },
+    { "zh", "chinese"    },
     { "en", "english"    },
-    { "ge", "german"     },
+    { "de", "german"     },
     { "it", "italian"    },
-    { "po", "portuguese" },
-    { "sp", "spanish"    },
+    { "pt", "portuguese" },
+    { "es", "spanish"    },
     { "ja", "japanese"   },
     { "ko", "korean"     },
     { "fr", "french"     },

tools/tts/README.md

@@ -20,7 +20,7 @@ Common params:
 ## Qwen3-TTS
 
 Available params:
-- `--tts-lang` can be `cn`, `en`, `ge`, `it`, `po`, `sp`, `ja`, `ko`, `fr`, `ru` (default: `en`)
+- `--tts-lang` can be `zh`, `en`, `de`, `it`, `pt`, `es`, `ja`, `ko`, `fr`, `ru` (default: `en`)
 - `--tts-speaker-file` should point to a speaker reference audio file (wav, mp3)
 
 Example usage: