No slow speed for German male voice
The speed of the German male voice is the same, normal, speed when you click the slow speech button.
Update: Seems to afflict the French male voice as well.
Portuguese male voice too. I have reported this a couple of times, still a problem. Have you filed a bug report? If not, please do so. https://support.duolingo.com/hc/en-us/requests/new
I am seeing this as well and filed a bug report.
Side note his accent is terrible. The first word in his sentences make Sie sound like Der, but that's another thing.
Not just the male voice, but female as well.
Looks like it affects any listening exercise.