How to specify language codes
Dubbing uses BCP-47 codes for both the source language (spoken in your file) and the target languages you want back. In the REST body those fields are src_lang / target_langs; in the Python SDK they are source_language_code / target_language_codes.
Supported languages
The same 12 codes are valid for both source and target.
Odia is or-IN for dubbing. od-IN is not accepted. If you have code that sends od-IN for Odia elsewhere, it will be rejected here with a 422 unprocessable_entity_error.