Each one of those regions had its own language, eg Egyptians spoke Egyptian, Romans spoke Latin, Arabians spoke Arabic, etc. There is no indication in the text that hundreds of different languages were recognized. That is pure speculation, unless you have some historical evidence that shows that each region had dozens of languages that were completely foreign to others within the same region. If each of the disciples (whether 12 or 120) were spread out among the temple courts then there was easily enough space to prevent them drowning each other out.
In any case scripture is clear - it was "them" (the disciples) who were speaking in the foreign languages of the crowd, not a voice in their heads.
Acts 2:6 "And when this sound occurred, the crowd came together, and were bewildered because each one of them was hearing them speak in his own language. "
The plain reading of that verse cannot be interpreted in any other way. If someone said "I heard a Frenchman speaking English" it doesn't mean the Frenchman was speaking gibberish, but a voice in my head miraculously translated it into English. It means what it says - the Frenchman was speaking English.