I tested an older webcam ..... non-uvc compliant ..... and had audio issues with it ...... so thought it might be similar with your cam.
no audio with my Creative cam..plain video cam ...... using a mic for sound recording .. and its sped up like crazy... can't change the sample rate
Is the video recording properly without sound? ...... sound unticked ....
Does it play back at the correct speed?
On the audio tab you select the Audio API ..... Portaudio or PulseAudio if you have PA installed.
Then select the MIC from the list of devices (if you have more than one available try each in turn)
Then you should be able to select the audio sample rate ..... from the drop-down list
Channels - Mono
Audio Format MP3 to begin with.