For now, Overdub is only available in English.
Overdub works differently than recorded audio in the script track. You can't adjust the word boundaries or use the Timeline tool on sections of Overdub audio. Converting it to audio will convert your Overdub into an audio layer that you can edit like you would audio in the Timeline.
To convert a section of Overdub into audio, hover over the Overdub layer in the TImeline and select convert to audio.
If you're only seeing the wordbar, you'll need to expand the Timeline