I’ve heard that if a Cantonese speaker and a Mandarin speaker are sharing a newspaper on a train, one can read out loud to the other and not be understood, but each can read the newspaper silently himself just fine. This sounds similar to how Portuguese speakers and Spanish speakers share a similar written language, but they’re speech sounds different and they are considered different languages. Why are Mandarin and Cantonese only considered dialects of each other and not different languages? When did the split between the two occur?
