GitLab

Summary:
``words`` field of CTCHypothesis is empty if no lexicon is provided, which produces confusing output (see issue https://github.com/pytorch/audio/issues/2584) when following our tutorial example with lexicon free usage. This PR adds a note in both docs and tutorial.

Followup: determine if we want to modify the behavior of ``words`` in the lexicon free case. One option is to merge and then split the generated tokens by the input silent token to populate the words field, but this is tricky since the meaning of a "word" in the lexicon free case can be vague and not all languages have whitespaces between words, etc

Pull Request resolved: https://github.com/pytorch/audio/pull/2603

Reviewed By: mthrok

Differential Revision: D38459709

Pulled By: carolineechen

fbshipit-source-id: d64ff186df4633f00e94c64afeaa6a50cebf2934