I highly recommend, for people interested in such things, Bill Bryson's book Made in America. In addition to discussions on some American inventions, it discusses at length why American language is the way it is, particulary why it's different from English spoken in mother England, and why there are so many regional differences in America. I wish Canadian English had also been discussed in the book, as many of the same explanations apply. For example if an area was settled by Welsh or Irish or Germans or Swedes, or Puritans unique pronounciations and well as peculiar word usage evolved.
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