Spanish Diphthongs and Triphthongs

Quick Answer

The combination of two vowels together in the same syllable is called a diptongo(diphthong) in Spanish. A three-vowel combination is called a triptongo(triphthong).

For example, the word viernes(Friday) contains the diphthong ie in the syllable vier. The word vieira(scallop) contains the triphthong iei in the syllable viei.

Spanish Diphthongs

What is a Diphthong?

A diphthong is a sound formed by two vowels in a single syllable. In Spanish, diphthongs can be formed by combining a strong vowel (a, e, or o) and a weak vowel (i or u), or by combining two weak vowels.

When a diphthong is made up of a strong vowel and a weak vowel, the strong vowel is stressed a bit more than the weak vowel. Check out some examples below!

Spanish Diphthong Pronunciation

Below are examples of Spanish diphthongs and their pronunciations.

Diphthong	Pronunciation	Examples
au	ow	aula, aunque
ai, ay	ay	aire, hay
eu	ehoo	Europa, neutro
ei, ey	ey	reina, rey
ia	yah	piano, hacia
ie	yeh	tierra, serpiente
io	yoh	radio
iu	yoo	viuda, ciudad
oi, oy	oy	boina, hoy
ua	wah	agua, cuadro
ue	weh	fuego, trueno
ui	wee	fuimos, fuiste
uo	woh	cuota, individuo

Is Y A Vowel?

The letter yis pronounced like a vowel when it appears at the end of a word and is preceded by another vowel.

For example: hoy(today), hay(there is/there are), and Uruguay(Uruguay).

Spanish Diphthong Accentuation

Written accents are called tildes(tildes) in Spanish. Here are a few tips to help you know when and where to place written accents on words that contain diphthongs.

Tips for Writing Accents on Dipthongs

Tip	Examples
Never accent words with a single syllable.	pie(foot), cruel(cruel)
Always accent words stressed on the last syllable that end in n, s, or a vowel (excluding y).	camión(truck), después(after), bonsái(bonsai), *but* virrey(viceroy)
Always accent words stressed on the penultimate syllable that end in a consonant other than n or s (including y).	huésped(guest), diésel(diesel), póney(pony)
Always accent words stressed on the third-to-last syllable.	ciénaga(swamp), náutico(nautical)

Accents and Weak/Strong Vowels

Confused about accents and weak vs. strong vowels? Here are some handy tips!

Tip	Examples
If a stressed diphthong is a combination of a strong and a weak vowel, place the accent on the strong vowel.	acción(action), alféizar(windowsill), terapéutico(therapeutic)
If a stressed diphthong is a combination of two weak vowels, place the accent on the second vowel.	acuífero(aquifer), cuídate(take care), veintiún(twenty-one)

So, Whatever Happened to the Accent On Guion?

The word guion(script, hyphen) used to have a tilde on the letter o. It was perceived as having two syllables and, according to Spanish rules for words ending in n or s, required an accent on the final syllable (e.g., guión). However, many Spanish native speakers, particularly those in Latin America, actually pronounce this word as a monosílabo(monosyllable). In general, Spanish monosyllabic words aren’t accented, so there was discussion about whether guion and similar words should or should not bear a written accent. Finally, it was decided that they should be considered monosyllabic for spelling purposes (pronunciation is a free country), so words like guion and truhan(rogue) lost their tildes. The decision was controversial and, to this day, some well-known authors and many other native speakers refuse to use the unaccented form.

Spanish Triphthongs

Triphthong Doesn’t Exactly Trip Off The Tongue

It doesn’t, but the concept is simple: it’s a combination of three vowels pronounced in the same syllable. In Spanish, triphthongs aren’t as common as diphthongs. They are formed by combining a weak vowel (i or u) plus a strong vowel (a, e, or o) plus a weak vowel again. In triphthongs, the strong vowel is stressed a bit more than the weak vowels.

Spanish Triphthong Pronunciation

Below are some examples of Spanish triphthongs and their pronunciation.

Triphthong	Pronunciation	Examples
uai, uay	way	aguaitar, Uruguay
uei, uey	wey	puntuéis, buey
uau	wahu	guau
iai	yahy	apreciáis, confiáis
iei	yehy	despreciéis, vieira
ioi	yohy	opioide
iau	yow	miau

Spanish Triphthong Accentuation

Written accents on words that contain triphthongs follow the same rules as those seen above for diphthongs, for example: buey(ox), miau(meow), estudiáis(you study), limpiéis(you clean), etc.