Config for SPEECH_TRANSCRIPTION.
Required. *Required* The language of the supplied audio as a `BCP-47
Optional. Maximum number of recognition hypotheses to be returned. Specifically, the maximum number of ``SpeechRecognitionAlternative`` messages within each ``SpeechTranscription``. The server may return fewer than ``max_alternatives``. Valid values are ``0``-``30``. A value of ``0`` or ``1`` will return a maximum of one. If omitted, will return a maximum of one.
Optional. If set to ``true``, the server will attempt to filter out profanities, replacing all but the initial character in each filtered word with asterisks, e.g. "f***". If set to ``false`` or omitted, profanities won't be filtered out.
Optional. A means to provide context to assist the speech recognition.
Optional. If 'true', adds punctuation to recognition result hypotheses. This feature is only available in select languages. Setting this for requests in other languages has no effect at all. The default 'false' value does not add punctuation to result hypotheses. NOTE: "This is currently offered as an experimental service, complimentary to all users. In the future this may be exclusively available as a premium feature.".
Optional. For file formats, such as MXF or MKV, supporting multiple audio tracks, specify up to two tracks. Default: track 0.