According to this teaching, when and why did different languages and dialects appear?

Les explains that the Greek word for tongues does not mean an unknown gibberish but a language, an understandable language. He ties the existence of many dialects and languages to the Tower of Babel, saying that ever since Babel there have been all kinds of dialects and languages throughout the then-known world. He also notes that the Jews had been out in dispersion: the ten tribes of the southern kingdom went into captivity into Syria about 775 B.C. and never really came back as tribes, while the southern two tribes of Judah and Benjamin were later taken captive to Babylon, with only a few thousand returning after 70 years; the rest were assimilated into the Middle East. He illustrates this with immigrants in America, whose children often learned the parents’ native language first, remaining bilingual until later generations lost the mother tongue and adopted English. So the context presents diverse languages and dialects as an established reality from Babel onward.