This is fascinating. I'm only a recent listener of hip-hop (primarily because of Earl Sweatshirt and Odd Future) and I'm in awe of the vernacular.

And similarly, as a boredom exercise a few weeks ago I did some lexical analysis of the song Timber (the monstrosity was being constantly played on the radio at the time) and here's what I came out with:

"83.1% of the words in the lyrics are five letters or less, 58.9% are four letters or less. The lexical density (the number of unique words divided by the total number of words, multiplied by one-hundred) is 29.1%. There is only one word in the song which has three or more syllables. Eleven people were involved with the writing of the song, each of them capable of producing just nine unique words each."