It has previously been shown that music features progressively more swear words and profanities per word uttered over time, and that rap music is at the forefront of this change. Therefore, this study explores whether there have been significant changes in swear word usage in rap music between the genre's conception (1970s-1980s), its commercialization (1990s-2000s), and its current black rights and personhood movements (2010s), totaling 50 years from 1970 to 2019. This was studied through a corpus of 300 song lyrics with 100-song sub-corpora per key period. These corpora were analyzed in terms of frequency of swear words and their functional categories based on McEnery and Xiao's (2004) model of swear words. The ten most frequent swear words changed significantly between the 1970s-1980s and 1990s-2000s sub-corpora. These results suggest that rap music initially featured few swear words to facilitate commercialization before normalizing larger frequencies. Furthermore, none of the corpora saw the same combination of most frequent swear words, although the 1990s-2000s and 2010s showed some overlap. Regarding functions, there were significant changes chronologically through the sub-corpora, with particular increase in literal usage.