Adam Clarke on 1 Corinthians 14:18

I speak with tongues more than ye all - He understood more languages than any of them did: and this was indispensably necessary, as he was the apostle of the Gentiles in general, and had to preach to different provinces where different dialects, if not languages, were used. In the Hebrew, Syriac, Greek, and Latin, he was undoubtedly well skilled from his education; and how many he might understand by miraculous gift we cannot tell. But, even literally understood, it is very probable that he knew more languages than any man in the Church of Corinth.