I am not sure if there was ever a commercial voice recognition hardware for cpc, but this looks really cheap and from what it looks like can feed a cpc serial port with commands based on pre-learned voice commands.
Might be cool.
https://www.ebay.com.au/itm/304556922583?mkcid=16&mkevt=1&mkrid=705-154756-20017-0&ssspo=9cyiRBWrRUO&sssrc=2349624&ssuid=MoUolhL3Tzu&var=&widget_ver=artemis&media=WHATS_APP
Ha I remember reading in a Pixel issue a long article about such a device for home computers. Must have been in the late eighties, and it sounded just like science fiction...
I knew I'd seen it somewhere (bottom of page):
https://archive.org/details/AmstradComputerUser11-1085/page/n49/mode/1up
Review of the C64 version (page 6):
https://ia800605.us.archive.org/19/items/home-computing-weekly-114/Home_Computing_Weekly_114.pdf
Review of the C64 version (page 23):
https://archive.org/details/your-computer-magazine-1985-08/page/n22/mode/1up?view=theater
Related:
http://www.vgmpf.com/Wiki/index.php/Voice_Master
Voice master looks cool but I think these days speech recognition is much better. Soon we might have dictation into tasword or protext... it is 100% possible now with the use of the m4 card and Google and another device such as a phone.
It can work like this. Go to a dictation website developed for just that (I already have done this before using Chrome's voice recognition API). On the cpc as a background task fetch anything dictated and if there is any, output it.
But... using a device like the one above which only costs au$12 will likely cut out the need for Google, Chrome and another device to speak into.
This could be of interest too... err fail to upload PDF of 2,9 MB. It's the EasyVR-3 to be suggested.