alternatives May contain one or more recognition hypotheses (up to the
maximum specified in ``max_alternatives``). These
alternatives are ordered in terms of accuracy, with the top
(first) alternative being the most probable, as ranked by
channel_tag For multi-channel audio, this is the channel number
corresponding to the recognized result for the audio from
that channel. For audio_channel_count = N, its output values
can range from '1' to 'N'.