Speech doesn't work when it is noisy or privacy is required. A similarly non-invasive interface is a hand holdable, or wearable chordic input device, like the one in the Hip PC:
https://steemit.com/introduceyourself/@brindleswan/forgotten-history-of-wearable-computing-a-steemit-exclusive
Noise is a problem now because the proper filtering algorithms don't work so well, but good AI will do it. Privacy though, that's a problem so in those cases it may require inventions like yours or miniaturized non-invasive neural readers in something like a headphone set.