Sphinx is just for the automatic speech recognition (ASR) part. But there are better solutions for that:
Kaldi (https://kaldi-asr.org/) is probably the most comprehensive ASR solution, which yields very competitive state-of-the-art results.
RASR (https://www-i6.informatik.rwth-aachen.de/rwth-asr/) is for non-commercial use only but otherwise similar as Kaldi.
If you want to use a simpler ASR system, nowadays end-to-end models perform quite well. There are quite a huge number of projects which support these:
RETURNN (https://github.com/rwth-i6/returnn) is non-commercial TF-based. (Disclaimer: I'm one of the main authors.)
Lingvo (https://github.com/tensorflow/lingvo), from Google, TF-based.
ESPnet (https://github.com/espnet/espnet), PyTorch/Chainer.
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