Someone has done a study to look at the richness of vocabulary used by some hiphop artists, compared with Shakespeare and Herman Melville’s Moby Dick. The study, by Matt Daniels, looked at the type/token ratio (TTR) in texts. This is how many unique words there are in a text compared with the total number of words. This is a rough measurement of the difficulty of understanding a text and of the text’s lexical richness. For it to be comparable you need to use the same length texts. In the study he looked at the first 35,000 lyrics or words of each artist.
He mentions some problems with the measurement, such as the variation in spelling to indicate pronunciation, but TTR is only intended as a general guide anyway. The results show that while most hiphop artists use a less wide vocabulary than Shakespeare, a few use a wider vocabulary in their lyrics. Some even use a wider variety of language than Melville.
TTR is crude, but fine for giving a gist. I’d like to think this study might lessen some people’s perception about Shakespeare being difficult to read, rather than show anything about the complexity of hiphop lyrics! It’s also a good study for making linguistics ‘cool’.