These cameras typically don't capture the best audio quality, the microphones in them are small, and the codecs that compress the audio are often times leave the audio having a distinct "sound" that makes it difficult to hear. You might be able to hear normal conversations, but I haven't had any luck with any cameras sensitive to capture whispers from a distance (even doorbell cameras don't too to well with whispering, and they're usually pretty close to the person speaking.) Your mileage may vary.
Also, make sure to check you local laws, many states forbid audio recording without the consent of others