Q: Why can't I use the headphones to hear (monitor) the microphone while recording?
The microphone signal is too weak to be heard in the headphones without
being amplified. The mic signal would need to be amplified by the
software (App) and played back through the headphones live for you to be
able to hear while you are recording. Most recording apps, including
the built-in recording apps, do not have a monitoring feature so the
headphones will only work for playback of recordings with these apps. If
you use a recording app with monitoring, like StudioMini or Fire by AudioFile, then you will be able to monitor while recording.