Explaining Intonation

It's come to my attention that not everyone knew what I meant when I said that Korean is not a tonal language.

A tonal language is a language whose meanings are affected by intonation, which refers to the rise and fall of the voice when speaking. Read this sentence: "The jury voted to convict Scooter Libby." Now read this one: "Convicts, like Scooter Libby, should serve their jail sentences immediately." The first sentence uses "conVICT," while the second uses "CONvict." It's the same word, but different intonation creates different meanings; intonation also affects meanings at the sentence level, though I'll leave you to come up with your own examples. Languages that aren't affected by intonation are easier to learn, all other things being equal.