The Classification insight contains track-level data.
track_data is an array containing an object for each track. Each object contains the track_id and track_label of the track, as well as the following:
spoken_languages - Array of strings containing RFC 5646 language codes for the language detected in the audio. For example, "en-US". Currently only the most predominant language is listed.
acoustics - Array of strings describing the acoustic environment. If a standard wide-band environment is detected, the array will be empty. Currently supported environments are: "telephone".