Acts 2:Verse 4
Began to speak divers tongues. Perhaps the apostles spoke only their own tongue, and the miracle consisted in each one’s understanding it as if they spoke it in his language. (St. Gregory of Nazianzus, orat. xliv.) — But St. Augustine and most others, understand the text literally; though the apostles had not this gift on all occasions, nor on all subjects, and therefore sometimes stood in need of interpreters. See St. Augustine, in Psalm xvii.; Expos. 2.; and Serm. 188. — The same Father observes, that the conversion of all nations to the Church, and their being united in one faith, all having one language or confession, is a perpetuation of the same miracle in the Church.
1 Corinthians 14:Verse 2
He that speaketh in a tongue, which others at least understand not: nay, which sometimes, perhaps, by the 14th and 15th verse, he himself that spoke tongues, did not understand, can only be said to speak to God. In spirit he speaketh mysteries, edifies himself, because in his spirit he is piously and devoutly affected; but he must endeavour that the Church, or people present, may be also edified. Let him then pray for the other gift of interpreting, what he speaks, or let another interpret. (Witham) — Not to men. Viz. so as to be heard, that is, so as to be understood by them. (Witham)