So Old English poetry has a fairly standard (though not set) number of syllables per line, which would be a better number to use to compare with the fastest known rappers (I checked around after seeing this and inevitably found a Reddit thread debating this question, but Eminem and Twista seem to be at the top).
In 2012 the Chicago Tribune was still reporting Twista as the holder of the world record (set in 1992), and I get the impression Eminem broke it, but I’m not entering the Eminem vs Twista debate here. What I need is a comparable rate, and Twista’s record is counted by syllable, not word, so his is easier to calculate. (Thank you Twista).
I can’t access the Tribune article, but it’s cited on Wikipedia, so I’m hoping the wiki text isn’t bullshitting:
So not looking at his peak burst as this is a marathon, he’s doing uhhh is this math right? He’s doing 10.87 syllables a second, holy shit.
So Old English poetry is structured in such a way where, while a poet didn’t have to count syllables, they did tend to end up with a fairly standard number of syllables per line (and a lot of alliteration). The beginning of Beowulf looks like this, for example:
You can see how the lines are pretty equal (the gaps in the middle of each line are added by editors because half-lines are important, you don’t have to worry about that) (Actually the lines are also decided by editors and no one agrees but that’s not a scop’s problem 💜).
The first line, for example, is 10 syllables : hwæt we Gardena in geardagum
*a lot of Gs are pronounced like y in OE, so that final word is more like yeh-ar-day-um.
The second has 9, the third 11. I should say I’m not sure about syllable counting in some lines, because vowel pronunciation rules vs stressed syllables rules are beyond me, having literally never been relevant to me until I needed to know how fast Twista (or Eminem) could rap Beowulf. Scops would be ashamed to be seen with me.
But for science’s sake let’s say there’s a range of of 9-13 syllables per line. Some paper I just found that I’m not totally sold on as a source but nevertheless seems to have done some math says the average is 9 syllables a line, roughly, though the range is from 6-18 and the most common single number is 10. Let’s go with that for now.
So, Twista can rap 10.87 syllables a second: more than an average line of Beowulf per second. But the copy of Beowulf we have is, as established, 3,182 lines long. Even just assuming an average of 9 syllables a line, that puts you at approximately 28,638 syllables. However, Twista can go at a rate of 652.36 syllables a minute.
Conclusion: if my math is right (please check my math) and if he could keep that pace up, Twista could rap the entirety of Beowulf in 43 minutes and 54 seconds. Presumably Eminem could do similar.