no sound form internal speaker and from internal mic

Just bought a IPhone 5 with a broken screen think I just needed to change the display assembly to have a working phone.

Now I realize that the only sound that work is the top earpiece (I can ear a person when I get a call) and the sound from my headphone jack.

Siri doesn't hear me. Voice memo either. Speaker phone doesn't pick up any sound from me and I can't hear anything. Video recording does not record any sound either.

I'm thinking about changing the internal speaker as well as the lightning/headphone/mic part to fix this.

Do you think it will solve my problem? I'm afraid it maybe related to a bad logic board. Any way to fix this? Anyone has any experience something similar?

Thanks in advance