# From Latin to Spanish: the sound changes that did the work

> id: origins.latin.sound-changes · category: origins · depth: standard · levels: B1 · review: internally_reviewed

**Summary.** A handful of regular changes turn most Latin words into their Spanish forms: F- → h-, stressed Ĕ → ie and Ŏ → ue, -CT- → -ch-, PL-/CL-/FL- → ll-, softened -p- -t- -c-, -NN- → ñ.

Sound change is regular rather than random, which is what makes it usable. The main laws between Latin and Castilian: initial F- became an aspiration and then silence, spelled h- (FARINAM > harina, FACERE > hacer, FILIUM > hijo, FUMUM > humo), except before the diphthong ue, where it stayed (FOCUM > fuego, FORTEM > fuerte). Stressed short Ĕ and Ŏ broke into ie and ue (TERRAM > tierra, PETRAM > piedra, SEPTEM > siete, PORTAM > puerta, NOVEM > nueve, MORTEM > muerte). Between vowels, -P-, -T- and -C- softened (LUPUM > lobo, VITAM > vida, AMICUM > amigo, CATENAM > cadena).

The consonant clusters are just as systematic: -CT- became -ch- (NOCTEM > noche, OCTO > ocho, LACTEM > leche, FACTUM > hecho, DIRECTUM > derecho); initial PL-, CL- and FL- became ll- (PLUVIAM > lluvia, PLENUM > lleno, CLAMARE > llamar, CLAVEM > llave, FLAMMAM > llama); -LL- gave the letter ll and -NN- gave ñ (ANNUM > año, CANNAM > caña), joined by -MN- and -NI- (DOMNUM > dueño, HISPANIAM > España). Final -M and often final -E simply dropped (PANEM > pan, SOLEM > sol, MARE > mar).

The payoff for learners is that this explains the stem-changing verbs. Latin stress fell on the stem in some persons and on the ending in others, and Ĕ and Ŏ only diphthongized when stressed — so you get puedo but podemos, tiene but tenemos, pienso but pensamos, duermo but dormimos, cuenta but contamos. The irregularity is not caprice; it is a fossil of where the Latin accent sat. The same split shows in noun–adjective pairs: hueso but óseo, huevo but oval, tierra but terrestre.

## Examples
- No puedo ahora, pero podemos hacerlo mañana. — I can't right now, but we can do it tomorrow. *(puedo vs podemos: the Ŏ of Latin POSSUM diphthongized only under stress. The whole stem-changing system is this one law.)*
- Anoche llovió y la puerta de hierro se mojó. — Last night it rained and the iron door got wet. *(noche < NOCTEM (-ct- → -ch-), llover < PLUERE/PLOVERE (pl- → ll-), puerta < PORTAM (Ŏ → ue), hierro < FERRUM (F- → h-).)*
- El lobo se bebió toda la leche. — The wolf drank all the milk. *(lobo < LUPUM (intervocalic -p- → -b-), leche < LACTEM (-ct- → -ch-).)*

Related: origins.latin.doublets, origins.latin.vulgar-latin-base, pronunciation.h-silent, conjugation.present.stem-o-ue

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