Tongues: A curse omen to Israel in unbelief

Among other functions, the phenomenon of "tongues" served as a warning to Israel to repent. Beginning with the curse sections of Leviticus 26 and Deuteronomy 28, and continuing on through the prophecies of Isaiah and Jeremiah, languages that were not understood by the Jewish people functioned as a warning that the most severe form of judgment was about to happen.

These "tongues" were spoken before Samaria fell to the Assyrian Empire in 722 B.C. They were spoken again before Jerusalem fell to the Neo-Babylonian armies in 586 B.C. And they were spoken again in the first Christian century before Jerusalem was destroyed by the armies of Rome in A.D. 70, as the Lord Jesus foretold.

So it is that Moses, Isaiah, and Jeremiah tell us that "tongues" are a sign to those who do not believe (1 Corinthians 14:21-22).