Diezmar is a more modern version of dezmar, meaning "to decimate".

Many verbs undergo diphthongization in their conjugations when stressed syllables fall on historic vowels /ɛ/ /ɔ/ from Latin. e.g.

  • pensar > pienso
  • poder > puedo

But I can think of no other examples where this diphthongization carries on into the (unstressed position) in the infinitive (and thus all conjugated forms).

The RAE claims the addition of the diphthong is due to the influence of (the noun) diezmo:


De dezmar, por infl. de diezmo.


Are there any other examples of verbs which have changed their form under the influence of a noun cognate? And if not, why did it happen with this verb? e.g.

  • dezmar > diezmar (por inf. de diezmo)
  • pensar > *piensar (por inf. de pienso)
  • contar > *cuentar (por inf. de cuento)

Note: I am not looking for instances of verbs which have diphthongs due to the Latin root having two neighbouring vowels e.g. orientar from Latin orns.

Etymological history of relevant terms:

enter image description here

Google Ngrams comparison of diezmar (earliest e.g. 1728) and dezmar (earliest e.g. 1610).

  • 1
    both amoblar and amueblar exist, in a similar process I imagine. Commented Dec 21, 2017 at 0:31
  • 1
    I would say most of what you can find will be covered by {noun + -ear} or {a- + noun + -ar}.
    – pablodf76
    Commented Dec 21, 2017 at 10:12
  • 2
    It's not exactly the same thing (vowel raising vs diphthongs) but they also maintain an unexpected infinitive stem (when it 'should' change from -e- to -i-, following the 'rules' of diphthongizing -ir verbs) due to them being more recent versions of classically -er verbs: spanishlinguist.us/2017/12/irregular-irregulars The rest are just other verbs which have alternative sets of conjugations/alternative spellings of the infinitive.
    – jacobo
    Commented Dec 21, 2017 at 10:44

2 Answers 2


Diezmar has a diphthong because of diezmo, as the DLE says.

This could have happened by backformation and re-derivation: once you have diezmo, you remove the suffix -o that makes it a regular masculine noun and then add -ar to turn it into a verb. There's another verb that means the same, but the speakers don't like the fact that it has another root and forget it in favor of the one they've created.

Or it could be because of analogy: dezmar has several very common obviously related words and they all have a diphthong, so the verb changes to match the rest of the family. The noun diezmo was probably more common than the verb, and it was "backed up" by the extremely common numeral diez (and dieciséis, diecisiete, dieciocho, diecinueve). The only other form of this historical root that doesn't have the diphthong when stressed is décimo, but it is a bit technical and not nearly as common as the numerals.

In general one would expect that "irregular" vowel-alternating verbs would become regularized, as has happened in a few verbs like prestar and entregar (whose Latin roots had lax /ɛ/ and which had forms like priesto and entriego in Old Spanish).

There are however a few cases of regular verbs (with a Latin root in /e/) that actually took the other way and diphthongized, like sembrar and colar.

If you loosen the requirements a bit, you can find a lot of newer verbs that have a diphthong in all forms (that is, they don't alternate). However that's not because they've shifted from older alternating forms but because they were derived from nouns where the Latin root had a short (later lax) vowel which then turned into a diphthong. Since Spanish noun inflection never shifts the stress, nouns don't alternate vowels, so if a noun acquired the diphthong, it stayed there in every word that was derived from it.

So we have e. g. puente from Latin pŏntis, but the modern verb that means "to go over sthg./sbdy.; to make a direct connection in a circuit" is puentear, because it was formed on modern puente + -ear. In the same way there is fiestear < fiesta < Latin fĕsta (but festejar "to party, to celebrate* keeps the monophthong /e/ in the first syllable), and afiebrarse < fiebre < L. fĕbris (but we also have the somewhat cultured febril), and cuerdear < cuerda < L. chŏrda (but also cordón and cordaje).


Influence of verb forms

This additionally happened with adestrar, amoblar, desosar:

Less frequently, the diphthong forms prevailed, producing the following modern regular verbs (with diphthongs in all 47 conjugations): 25

enter image description here


25 For each of these verbs, the “old” (mixed diphthong pattern) forms still exist but are rarely used: adestrar, dezmar, amoblar, desosar.

And also with the Old Spanish verb levar > *lievar > llevar:

The shift of an initial 'l' to 'll' is not normal, but is explained by the fact that in Medieval/Old Spanish, the third-person present indicative was lieva, which was then altered into lleva; eventually this was extended to the entire verb.1


1. Diccionario Crítico Etimológico Castellano (G-MA), Joan Corominas

enter image description here

Influence of nouns

There are many more examples of this happening under influence of a cognate noun with diphthongization:

e > ie

o > ue

  • pontear, puentear
  • cordelar, cuerdear


Similar phenomena:

cerner/cernir, hender/hendir
ergir (yer-/ir-), Spanish Verbs Made Simple(r) - By David Brodsky (Search "alternative")
Past participle doublets
Vowel heightening (o > u): podrir, pudrir; jogar, jugar; troncar, truncar; torrar, turrar; tollir, tullir; tollecer, tullecer; noroestear, noruestear (norueste)

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