In Acts 2, does the word 'tongues' refer to real languages or to gibberish?
In Acts 2, 'tongues' refers to real, understandable languages, not unknown gibberish. The Greek word means a language, an understandable language. Since Babel, many dialects and languages existed, and dispersed Jews were present, so the tongues spoken were actual languages that hearers could recognize.
Les teaches that the Greek word for tongues does not mean an unknown gibberish; it means a language, an understandable language. He connects this to the Tower of Babel, after which there have been all kinds of dialects and languages throughout the then-known world. Many Jews were in dispersion: the ten tribes went into captivity into Syria about 775 B.C. and never really came back as tribes, and later Judah and Benjamin were taken to Babylon, with only a few thousand returning after seventy years. The rest were assimilated into the Middle East. Les illustrates this with immigrants to America: parents tried to learn English, but their children often learned the parents' native language first, becoming bilingual until later generations lost the mother tongue. Thus the tongues in Acts 2 were known, understandable languages, not gibberish.