Dictation stopped working macOS Monterey version 12

Hi there, I have found a workaround. I added "Canadian English" as an additional dictation option so whenever my regular dictation option won't work I just change to the Canadian English diction and it continues to work.

Also, restarting also makes the trick

Hi MCS2010,

Welcome to Apple Support Communities. We understand that you're having an issue with using Dictation on your iMac. We'd like to help.

While it's challenging to know what caused a previous issue after it's resolved, we can provide you with steps to help in the future if it returns:

If Dictation on Mac doesn’t work as expected

If you’re having trouble using Dictation on your Mac, something may not be set up correctly. Here are some solutions to try:

1. Be sure Dictation is turned on in the Keyboard settings.

Note: If you can’t turn on Dictation, Screen Time Content & Privacy Restrictions may be preventing you from using it. A family organizer for a Family Sharing group can set up Screen Time for a child and restrict access to Siri & Dictation. See Change App Restrictions settings in Screen Time. Also, when Voice Control is on, you can’t use Dictation.

2. Choose the correct language and dialect. See Dictate messages and documents.

3. Be sure you’re using the correct dictation keyboard shortcut.

4. Be sure your system has a valid internet connection—choose Apple menu  > System Settings, then click Network  in the sidebar. (You may need to scroll down.)

If this happens again, let us know and we'll try to help isolate the issue.

Take care!