ἑτέρῳ γένη γλωσσῶν, ἄλλῳ δὲ ἑρμηνεία γλωσσῶν

heterō genē glōssōn, allō de hermēneia glōssōn

…to another, kinds of tongues; and to another, interpretation of tongues.

The Spirit distributes "as He wills" (12:11) — and what He distributes here is kinds of tongues. The variety is not our invention; it is written into the list of gifts. Hold that, and the rest falls into place.

ὁ λαλῶν γλώσσῃ οὐκ ἀνθρώποις λαλεῖ ἀλλὰ τῷ θεῷ … ἑαυτὸν οἰκοδομεῖ

… ouk anthrōpois lalei alla tō theō … heauton oikodomei

One who speaks in a tongue does not speak to men but to God … he builds himself up.

Here the tongue is directed to God, not to people — prayer and praise "with the spirit" (14:15), edifying the one who prays. Paul practiced it gladly: "I speak in tongues more than you all" (14:18). This is the devotional kind — private, between a person and the Lord.

ἤρξαντο λαλεῖν ἑτέραις γλώσσαις καθὼς τὸ πνεῦμα ἐδίδου ἀποφθέγγεσθαι

ērxanto lalein heterais glōssais … apophthengesthai

…they began to speak in other tongues, as the Spirit gave them to utter.

Galileans spoke, and Parthians, Medes, Elamites, and the rest each named their own native language (2:8–11). These were real human tongues, never learned by the speakers — a sign to the nations gathered for the feast. Here the gift is recognizable, earthly speech.

ἤκουον εἷς ἕκαστος τῇ ἰδίᾳ διαλέκτῳ … πῶς ἡμεῖς ἀκούομεν ἕκαστος;

ēkouon heis hekastos tē idia dialektō … pōs hēmeis akouomen;

…each one heard them speaking in his own language … how do we each hear in our own?

Notice where the text puts the wonder — on the hearing: "we hear, each in our own language." With perhaps a hundred and twenty speaking at once, could any one foreign tongue be picked out of that sound? It is reasonable to ask whether the Spirit also worked on the ears — that each hearer received the praise of God in his own language. A case, held with the text, not against it.

… καὶ εἷς διερμηνευέτω· ἐὰν δὲ μὴ ᾖ διερμηνευτής, σιγάτω

… kai heis diermēneuetō; ean de mē ē … sigatō

…and let one interpret; but if there is no interpreter, let him keep silent in the church.

Public tongues need a companion gift — interpretation — so the whole body is built up, not just the speaker (14:5). Two or three, in turn, one interpreting; otherwise, speak to yourself and to God (14:28). This is the congregational kind, governed by love and order.