Hi @Keifus - thanks for reporting. This is a known issue and something that the team has investigated here - https://github.com/brave/brave-browser/issues/3725.
Here’s the most relevant comment from the issue:
"Hi folks, sorry for the lack of update here. It’s a bit of a gnarly issue, and it gets me hopping mad.
First of all: this isn’t a problem with the microphone — it’s a speech recognition API. Chrome ships with a non-standard API used for speech recognition. Websites which call the API are asking the browser to transcribe audio on behalf of the website and send the site the transcribed text (not the audio). When a site calls this API in Chrome, Chrome sends the raw audio to a Google server for transcription. The Google server parses the raw audio, and send the transcribed text back to Chrome. Chrome then passes the text to the website.
There are two problems with this. The simple straightforward problem is that Brave doesn’t have access to that Google transcription service. It’s a paid service from Google which Chrome gets to use for free. If Brave wanted to use it, we’d have to pay Google for the privilege. The second and much more substantial issue is that I don’t think that anyone reasonably expects clicking a microphone icon on Duolingo to result in Brave sending their audio to Google .
Honestly, I think that this design in Chrome is absolutely ridiculous and I was completely flabbergasted when I learned how it worked. We’ve had some conversations with Google about it, and the outcome is more or less (1) that they don’t see what the issue is, and (2) they won’t give us access to this online transcription service unless we pay for it.
So the upshot here is that Google has built speech recognition on Google sites like Google.com and Google Translate so that they depend on a non-standard API in Google’s web browser which actually just calls back to a Google transcription service. You may be wondering why Google.com and Google Translate don’t just take the audio and use that Google transcription service behind the scenes rather than doing this elaborate approach involving the browser. Reader, I have exactly the same question. But the outcome is that speech recognition on these Google sites only works in Google’s browser, which might be all the answer you need.
Unfortunately, I don’t think there’s any way forward here. Our current plan is to disable things so that the microphone icon doesn’t show up. Obviously, that’s not a great solution: it’s more like hiding the problem. But I don’t know what else to do. And this is all Google’s fault."