"pop" when pressing touch screen keys AND qwerty keyboard

My phone began making a very, very short pop when I press a key.  It does it on both the qwerty keyboard and the touchpad.  Does anyone know if this is a sign that my phone is aging and will soon die? 

Thank you for your quick reply!  Yes, it's from the speaker but it doesn't make any pops when I use the music player.  It's a tiny pop a millisecond before the phone makes its sound.  And I had already did what you said but that didn't fix the problem.  I mean, sure, it doesn't make the pop sound, but it's muted and I like for the phone to make beeps or whatever.  Oh, and it DOES make the pop sound when I get a text or when it rings.  It's all about the speaker, I know.  I'm just worried the phone is going to quit working altogether.  The touch part is already getting a bit sketchy (I play "bookworm" on my phone at least an hour a day and it's all touch).  So, anyway, I was hoping that someone might know what's going on with it.  It's very odd.