Clarence Major, in his study "Juba to Jive: A Dictionary of African-American Slang", traces the origins of hip to the Wolof verb hepi ("to see") or hipi ("to open one's eyes"), and dates its usage in America to the 1700s. So from the linguistic start, hip is a term of enlightenment, cultivated by slaves from the West African nations of Senegal and coastal Gambia. The slaves also brought the Wolof dega ("to understand"), source of the colloquial dig, and jev ("to disparage or talk falsely"), the root of jive. Hip begins, then, as a subversive intelligence that outsiders developed under the eye of insiders. It was one of the tools Africans developed to negotiate an alien landscape, and one of the legacies they contributed to it. The feedback loop of white imitation, co-optation and homage began immediately.
(I edited the above paragraph a bit; either I'm not hip to Leland's frequent use of like or somebody at MSNBC did a bad global replace.) That makes me want to track down both Leland's and Major's books, although the latter may have to wait -- Amazon lists used copies starting at $55! Time for a reprinting. (Via Negrophile.)
On a completely different subject, Language Hat quotes at length from a piece by Keki Daruwala on language in Indian poetry. I'm surprised that Daruwala scoffs at code-switching in poetry; it's extremely common in Chicano and other US latino poetry. But maybe (a wild guess here) the conventions of poetry in other Indian languages diverge enough from those of English that the result would be a clash of genres as well as languages. Which makes me think that's just the kind of challenge some writers would choose to confront head-on.