That's a sensor board containing a microphone.
The A0 output is some kind of analog signal - the microphone also produces an analog signal - but without further information it's not sure what that analog signal is. I wouldn't be surprised if it's some kind of level envelope rather than actual sound signal.
You better just buy a separate microphone. Or break open two of your old mobile phones and harvest the microphone out of them. Usually much smaller than the one on that module, which may be a plus as well.