I've been hearing a foreign convention from my phone

[Android Central Question]

I've been hearing a foreign conversation coming from my phone even when if the phone is in silence mode, it happens every three or four days , when I hear this I take the phone and I don't see nothing unusual, and also sometimes out of the blue it vibrates , even when I'm on a call talking ey someone and the person says what is that ?I don't know how to explain

 

[B. Diddy]

Welcome to Android Central! Which phone? Is it coming through the main speaker or the earpiece? Does it happen in Safe Mode as well?