I develop kaldi-active-grammar [0]. The Kaldi engine is state of the art for command and control. Although I don't have the data and resources for training a model like Microsoft/Nuance/Google, being an open rather than closed system allows me to train models that are far more personalized than the large commercial/generic ones you are used to. For example, see the video of me using it [1], where I can speak in a relaxed manner without having to over enunciate and strain my voice.
Gathering the data for such training does take some time, but the results can be huge [2]. Performing the actual training is currently complicated; I am working on making it portable and more turnkey, but it's not ready yet. However, I am running test training for some people. Contact me if you want me to use you as a guinea pig.
[0] https://github.com/daanzu/kaldi-active-grammar
[1] https://youtu.be/Qk1mGbIJx3s
[2] https://github.com/daanzu/kaldi-active-grammar/blob/master/d...