Why does Dictation stop working on my M1 MacBook Pro running Sequoia 15.3.1?

I have an M1 MacBook Pro, 14" running Sequoia 15.3.1. I am a lousy typist and so dictation is easily the most used feature on my computer. It works smoothly for a few days and then simply stops working, i.e., selecting it in the edit menu or using the keyboard shortcut produces a lower tone, clunk sound as opposed to the customary on/off tones and the feature won’t start. A reboot usually returns it to working order but not 100% of the time. This behavior existed before upgrading to Sequoia and has been an ongoing issue for several months to a year. Every search for a solution has led to the same results: check this; check that; etc. Everything always checks. My system settings have not changed. It just stops working. Has anyone else experienced this issue and if so, has anyone found a fix?

BTW, Siri has always worked so far. 

[Re-Titled by Moderator]