This is what I bumped into over the last 2 days.  I think i've also
   seen speech to text models in model zoos.  I have trouble navigating
   the internet around this.
   [1]https://github.com/PaddlePaddle/DeepSpeech
   [2]https://github.com/kaldi-asr/kaldi
   [3]https://cmusphinx.github.io/

References

   1. https://github.com/PaddlePaddle/DeepSpeech
   2. https://github.com/kaldi-asr/kaldi
   3. https://cmusphinx.github.io/