I'm an admirer of a wonderful book called The Power of Babble (that's right, "Power"), by Alex McWhorter, who is a great writer on language and social-cultural matters.

McWhorter maintains that there is no such thing as language: "It's all dialects!" Some of the dialects mutually understandable, to one degree and another, and some are not. Look at the Italian native to Naples and Spanish. They are nominally parts of separate languages, but they are pretty much mutually comprehensible--more so, it might be said, than Naples Italian and northern Italian.

The concept of "language", I think, is like "species" in biology, where it can meaningfully be said that "A species is whatever expert biologists decide to call 'a species'." Ditto "language".

It's ALL dialects!

Dave Oesterreich