I've created a Windows7 WVD and successfully accessed to it. Everything's working fine except Speech Recognition (i.e. mic redirection). I'm accessing to WVD via "Microsoft Remote Desktop" on macOS and the default Remote Desktop on Windows OS with using a RDP file. Both clients didn't work.
Here are what I tried or checked:
1. Tried Control Panel > Speech Recognition > Start Speech Recognition
The error message said "Wizard could not launch, No audio input device found."
2. Go to Device Manager
No sound device found
3. Added these RDP options to the RDP file.