How do I enable on-device dictation?

I struggle to get on-device dication going on my M1 Mac. I know that it is not working, because dictation terminates after 60 seconds. A footnote on macOS Monterey's Features page says that this feature "requires download of speech models". How can I download these models? I would like to enable on-device dictation in German (Germany).

On-device Dictation is activated using the Voice Control section of the Accessibility System Preference pane.

Once you have turned on "Enable Voice Control", then the appropriate language pack will be downloaded, based on the language in the Dictation tab of the Keyboard pane.

Voice Control is completely separate from 'Dictation' (which is entirely Siri-based), and you can't have them both on. When Voice Control is on (and Awake), then not only can you dictate into text fields, you can also issue commands like "Close Window".