1. Eminem - 8,818 unique words
2. Jay Z - 6,899
3. Tupac - 6,569
4. Kenye West - 5,069
5. Bob Dylan - 4,883
It should be noted that many artist/writers like Bruce Springsteen don't make the list because they haven't granted permission for Musixmatch to use their lyrics.
There have been other studies that have looked at parameters like lyric density and intervals between new words, but this is the first to check overall vocabulary size.
The study looked at 93 top artists across 25 different genres that ranged from pop to new age.
Personally, I'd just prefer to listen and not analyze. Do you think songwriter vocabulary matters?