Ha, I don't know anything at all about how language evolved. But, when you listen to somebody speaking--if you can bracket the meaning (which tends to soak up

Ha, I don't know anything at all about how language evolved. But, when you listen to somebody speaking--if you can bracket the meaning (which tends to soak up all our conscious attention)--you can hear the rhythm and you can hear the melodies. You can hear the music. In order to understand somebody who speaks English in a different enough dialect, you have to really listen to the rhythm and melody--in order to puzzle out the meanings. The meanings are not hitting you in the face, they are more coy, and you have to seek them out while listening to songs you've never heard before! Same goes with speaking with somebody who speaks English as a second language. You can hear the music in a way which is hard to do when listening to native speakers. Not impossible--once you realize what is happening, you can learn to pay attention to it. But think about all the different ways you've hear English spoken...French accents, Nigerian accents, German accents, Russian accents, north Indian and south Indian accents, Mexican accents,.....It's like turning into a radio station playing the music of the world. And unless they all were taking the time to learn English, we would not be hearing their music. And we would not be able to avail ourselves of an inexhaustible supply of new idioms, new ways of emphasizing, new ways of conveying subtle emotional cues...