Quid sonat equivocum simili sub ymagine vocum
Si dubius fueris, hoc lege! Tutus eris.*

Versus differentiales were a common feature of medieval grammar education from the 11th century on. The idea was to distinguish two homonyms in which the penultimate syllables had vowels of different lengths, such as ăcer “maple” and ācer “fierce”, and use them together in a hexameter verse. The scansion and the sense of the verse would make it clear which was which:

Dicitur arbor ăcer, vir fortis et improbus ācer.

Such verses are particularly valuable for three-syllable words, since a short middle syllable throws the stress back to the first syllable:

In silvis lépŏres, in verbis quere lepṓres>

This project was a spin-off of my dissertation on the 13th-century Anglo-Latin poet Henry of Avranches, who compiled two sets of versus differentiales. The idea was to compare Henry’s Comoda gramatice and Tractatus with John of Garland’s Accentarium, and draw some conclusions about the relations between the two poets. That project stalled in the mid-1990s and my career trajectory since then is not likely to lead to its completion. Instead, in the hope of entertaining and edifying, and of getting at last some value out of that unfinished work, I set up a Twitter bot in 2013 to tweet one of these little verses daily and post them to this site. Here I’ve included the apparatus of references, such as it is, but I can’t now guarantee it. The value, if any, is in the verses.

Note: The orthography is generally medieval, either that of the editions I’ve followed or of the manuscripts I’ve transcribed. If you see a problem or have a question, please feel free to contact me via Twitter or Github.

* Jacob Werner, Beiträge zur Kunde der lateinischen Literatur des Mittelalters (Aarau, 1905), p. 184.