hi.

in my project i prefer to make player put cellphone on his hear to simulate some talking or communication state.

i want to know can i use phone talking speaker to play sound for player.

thank you for helping.

I don't see a tag for the platform. Android, Apple, or something else?

On Android phones, you can tell the system your application is in "communication" mode, what you'd use for VoIP calls and similar.  Look up AudioSystem.setPhoneState(MODE_IN_COMMUNICATION) for more on that. It can have troubles with headsets depending on the hardware, but should otherwise allow you to route audio to the earpiece microphone instead of the louder speaker.