Apple Watch dictation

I had the same problem and didn’t figure it out for a while. Dictation is dependent on Siri being enabled. Make sure Siri is turned on on the phone, then the will carry over to the watch. At least in my case. Go to Settings > Siri and search and make sure it is turned on. If that does not work go to settings > general > keyboard, Then enable dictation at the bottom.

Try resetting your watch by pressing in the crown and side button until you see the Apple logo, then release both. Make sure your iPhone and watch have the latest updates.

Which Watch do you have? Check your Watch is updated to 5.2.1and your iphone is running ios 12.3.1 also you dictation is on on your iPhone.

Also in the watch app go to settings > General and Enable dictation