Acts 2:8

And how hear we, every man in our own language wherein we were born?

'AND HOW HEAR WE'-'And how is it' (NASV) We might say, 'How are they doing that?'

'IN OUR OWN LANGUAGE WHEREIN WE WERE BORN'-Even though Greek was almost universally spoken throughout the Empire, most districts or regions held on to their own dialects (Acts 14:11). Vincent notes, 'The Phrygians and Pamphylians, for instance, both spoke Greek, but in different idioms; the Parthians, Medes, and Elamites all spoke Persian, but in different provincial forms.' (Vincent p. 450)

Speaking in tongues was the miraculous ability to FLUENTLY speak in. foreign language and even in. certain regional dialect, that might only be spoken in one area. And to speak it the way. "native",. person born there and or raised in that region all their life would speak it.