Hearing or Speaking Tongues?

In Acts 2 Luke records the Pentecost event. I was recently taught from this chapter that the disciples were speaking different foreign languages, that is, languages that were native to those who heard them (v8). Someone afterward challenged me to rethink my conclusion. They suggested that the disciples were not speaking foreign languages, but a heavenly tongue. This is indicated by the fact that Luke says, "Each one was hearing them speak in his own language" (v6). In other words, the miracle was not that the disciples were speaking the language of the Parthians and Medes etc., but that the foreigners were hearing them in their own language.

I could understand how this argument might be plausible for two reasons:

Luke records that each person was hearing the disciples speak in his own language

Both the narration of Luke (v6) and the confession of the men (v8) note that they were hearing the disciples. As the disciples spoke in some heavenly language, the Holy Spirit enabled them to hear the group of disciples speaking their native tongue.

Luke records that each person was hearing them (the disciples) speak in his own language

Notice that Luke does not say, "Each one was hearing one of the disciples speaking in his own language" (v6). Luke uses the plural them (auton) which seems to indicate that not one, but the group of them were speaking (or perceived to be speaking) one's language.

Although these are plausible arguments I don't think the miracle was the men hearing the disciples, but the disciples speaking to the men:

1) Luke records that the disciples spoke in other tongues (v4)

The disciples were not speaking one heavenly language, but several languages. Granted, they could have each been speaking their own heavenly tongue, but the reader must bring that to the text. The natural reading of the text (given the context) is that they were speaking different foreign languages that were known to those hearing.

2) Luke records that the Spirit was influencing the disciples speech, not the peoples' hearing (v3)

The Spirit gave the disciples the ability to utter different languages, but it says nothing about the Spirit giving the people the ability to hear (interpret). The emphasis of the passage is on the Holy Spirit being poured out upon the disciples, not so much the foreigners. The spiritual gift seems to be tongues, not interpretation.

3) The passage of Joel indicates prophecy, not interpretation (v11, 17)

The prophecy of Joel is not that the Spirit would be poured out upon the people to hear other tongues (interpretation), but that the Spirit would give them the ability to prophecy, that is, to proclaim the mighty works of God (v11).

The miracle of Pentecost was that the Spirit was poured out upon his sons and daughters that they may prophecy of the mighty works of God. The Spirit enabled them to accomplish the kingdom work. This same promise is open for us today. Oh that the Spirit would be poured out among us that we may utter in foreign tongues the mighty works of God.