Making Macs more accessible is a minefield of conflicting requirements in which it’s so easy to address one requirement and lock many other users out. Following a couple of comments here, I’ve turned my attention to dictation and voice control, and how they’ve changed in Catalina.
In Mojave, Dictation is controlled in the tab of that name in the Keyboard pane. For this, I turned on Enhanced Dictation; although I don’t use this regularly, I have used it over several versions of macOS and am familiar with its performance.
Oddly, to access the commands available when dictating, you have to switch to the Accessibility pane, where the Dictation item offers a button Dictation Commands… which displays the set of built-in commands such as Select previous word. There’s an option to enable additional or ‘advanced’ commands there, and you can enable/disable individual items from the list, but you can’t add any custom commands.
Once enabled and set up, to use dictation all you do is press your designated key, by default the Function key pressed twice, and speak away when you’ve placed the insertion point in a view which accepts text input.
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