무슨 소리 야?
Someone can crack this phrase and explain it to me? I'm on a basic level of korean and I just came across with this question:
무슨 소리 야? What are you talking about? What do you mean? Thank you!

Question

Answer

I think you answered your own question, actually. 
It has the same meaning as 무슨 말이야/무슨 말이에요, though a little less formal and polite.
So literally it means "what kind of(무슨) sound(소리) is it (야)?"
I don't know if there are any other way to explain it, it is just a basic expression really.