Having the same/similar issue?
Option for Speec Rec. is ticked when I start, the window opens and says Connected (no errors), after I talk there's a ding- nothing happens and I also don't get any replies.
There are no options/configuration from what I can tell to specify the audio input/outputs sadly, but I tried to manually pick the input device in the Windows Volume Mixer to the correct microphone- still no luck.
There also doesn't appear to be an Enable Speech Recognition option inside the simulation in 'Simulation' -> 'Radios' like the documentation says (F1).