Skip to content

Sound laws · Law 2 · Vowels

Stressed short O breaks into ue / uo / eu

Ŏ (stressed)

Spanish

ue (open and closed syllables)

French

eu, œu (open syllable); o (closed)

Italian

uo (open syllable); o (closed)

Portuguese

o [ɔ] (no diphthong)

Romanian

o; oa [o̯a] when a or e follows (poartă, moarte)

Catalan

o [ɔ] (no diphthong)

What happened

The counterpart of the open-e change: Latin short Ŏ became an open [ɔ], which under stress split into a rising diphthong. Spanish made it ue in every stressed syllable; Italian made it uo only in open syllables. French also diphthongized it in open syllables, but its uo then fronted and fused into the single rounded vowel written eu or œu ([ø], [œ]). Portuguese and Catalan kept a plain open [ɔ]; Romanian kept o but broke it into oa when an a or e followed in the next syllable (poartă, moarte), a change that also caught long Ō (FLŌREM → floare).

Examples

LatinItalianSpanishFrenchPortugueseRomanianCatalanEnglish relative
NOVUM‘new’nuovonuevoneufnovonounounovel
FOCUM‘hearth → fire’fuocofuegofeufogofocfocfocus
OVUM‘egg’uovohuevoœufovoououoval
PORTAM‘door, gate’portapuertaporteportapoartăportaportal
FORTEM‘strong (ro foarte 'very')’fortefuertefortfortefoartefortfort
MORTEM‘death’mortemuertemortmortemoartemortmortal

Decoder

Spanish ue in a stressed syllable is Latin o: try o in Portuguese, Catalan, and in Italian and French when a consonant cluster follows (puerta → porta, porte), uo and eu when a single consonant follows (nuevo → nuovo, neuf). Romanian oa is the same o before a or e: poartă = porta.

Exceptions

A following yod blocks the Spanish diphthong (NOCTEM → noche, OCULUM → ojo, FOLIAM → hoja), and a nasal blocks the French one (BONUM → bueno, bon, buono). Italian has holdouts (NOVEM → nove, beside nueve, neuf), and modern Italian often drops the u after a palatal (figliolo, spagnolo). Portuguese marks the open vowel only by pronunciation (novo [ˈnovu] but nova [ˈnɔvɐ], by metaphony). Learned words keep o (novela, moral).

Watch it happen: FOCUM

In your word bank