ENG-87042: clarify TTS language parameter supports lowercase locales

openapi.yaml

@@ -10088,24 +10088,10 @@ components:
             - raw
         language:
           type: string
-          description: Language of input text.
+          description: |
+            Language or locale of input text. Accepts ISO 639-1 language codes (e.g., `en`, `fr`, `es`, `zh`) as well as locale codes for region-specific variants. Locale codes must be lowercase (e.g., `zh-hk` for Cantonese, not `zh-HK`).
           default: en
-          enum:
-            - en
-            - de
-            - fr
-            - es
-            - hi
-            - it
-            - ja
-            - ko
-            - nl
-            - pl
-            - pt
-            - ru
-            - sv
-            - tr
-            - zh
+          example: en
         response_encoding:
           type: string
           description: Audio encoding of response. Only applicable when response_format is raw or pcm. Cartesia models respect this parameter and support all values. Orpheus, Kokoro, and Minimax models always return pcm_s16le regardless of this setting.