Unfortunately, that information is wrong.
Although Opera has the JavaScript API thanks to its Chromium foundation, speech recognition does not work at all in the browser.
I’ve tested every demo I could find and none of them worked in Opera. One big problem is the missing permissions dialog when trying to start speech recognition. After that, the right JavaScript events simply aren’t triggered.
You can test it yourself using either this plugin or one of these demos:
https://zenorocha.github.io/voice-elements/#recognition-element
https://mdn.github.io/web-speech-api/speech-color-changer/
https://www.talater.com/annyang/
Also check out MDN’s browser compatibility table which is usually up to date: https://developer.mozilla.org/en-US/docs/Web/API/Web_Speech_API
I’ve opened an issue on GitHub as a reminder for me to regularly check support for Opera. Maybe they’ll fix that in the near future.
