Speaker is no longer working.

Hi. My girlfriend has an LG G2 phone and after Christmas it had fallen on its back and the screen cracked. Well he had a professional repair the screen and she had just realized the speaker doesn't work anymore. I restarted the phone to make sure it wasn't some software issue. The charge port and headphone port are still functioning. You think maybe the fall broke the speaker? And if I repaired it myself how much you think it would cost? Thanks.