Acts 2:4

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.