Among the most annoying things a Spanish learner has to deal with, we have the subjunctive mood, when to use ser or estar, and the irregular verbs. Today we’ll talk about the latter.
Irregularities come in many ways, one of them being the diphthongization of the verb root, as in dormir (infinitive), but yo duermo. There is a reason for this; it’s pretty nerdy, so you can skip the whole article if you aren’t into historical linguistics.
Your Spanish teacher has probably taught you that in this kind of verbs you diphthongize when the accent is on that syllable, and you don’t when the accent isn’t:
- dormir [dorˈmir]
- duermo, duermes, duerme, duermen [ˈdwermo, ˈdwermes, ˈdwerme, ˈdwermen]
- dormimos, dormís [dorˈmimos, dorˈmis]
So why is this? Why?
We have to go back to Latin evolution into Spanish. In Latin, as in British English (not so much in American), there was a difference in vowel length, as in “put” (short vowel) and “food” (long vowel), “shit” (short) and “sheet” (long), etc.
While long vowels generally resisted any kind of transformation, short vowels underwent many changes in the evolution, depending on their position in the word, on the accent, etc.
So, for example, Latin short /ŏ/ diphthongized into Spanish /we/ when stressed:
- Latin fŏrtem (fŏrtissimum) > Spanish fuerte [ˈfwerte], but fortísimo ‘very strong’ [forˈtisimo]
Latin long /ō/, however, remained /o/ in Spanish, stressed or not:
- Latin gloriam > Spanish gloria, not *glueria
Just in the same way, Latin short /ĕ/ diphthongized into Spanish /je/ when stressed:
- Latin terram > Spanish tierra, but terráqueo
This last rule also applies to verbs such as herir (< Latin fĕrire), but yo hiero, etc.