Act 2:6 Now when this was noised abroad, the multitude came together, and were confounded, because that every man heard them speak in his own language/dialektos.
Act 2:7 And they were all amazed and marvelled, saying one to another, Behold, are not all these which speak Galilaeans?
Act 2:8 And how hear we every man in our own tongue/dialektos, wherein we were born?
Act 2:9 Parthians, and Medes, and Elamites, and the dwellers in Mesopotamia, and in Judaea, and Cappadocia, in Pontus, and Asia,
Act 2:10 Phrygia, and Pamphylia, in Egypt, and in the parts of Libya about Cyrene, and strangers of Rome, Jews and proselytes,
Act 2:11 Cretes and Arabians, we do hear them speak in our tongues/glōssa the wonderful works of God.
Also, the word used is dialektos from which we have the word "dialect". This differs from the word" TONGUES" where the word used is glōssa.
So, they not only heard their own language/glōssa being spoken, they heard it spoken in the dialektos/dialect from where they were born.