Diphthongs in Spanish

What Are Diphthongs in Spanish?

Diphthongs (los diptongos in Spanish)are formed when two vowels are used together in the same syllable. Spanish has three strong vowels and two weak vowels which can form a total of fourteen permissible diphthongs.

Types of Spanish Diphthongs

There are three types of diphthongs in Spanish, depending on the combination of vowels:

Rising Diphthongs: weak vowel + strong vowel

Falling Diphthongs: strong vowel + weak vowel

Homogeneous Diphthongs: weak vowel + weak vowel

Rising Diphthongs

When a weak vowel (/i/ or /u/) is followed by a strong vowel (/a/, /e/, or /o/), a rising diphthong is formed. In many of these diphthongs, the weak vowel changes into a gliding semivowel (/j/ and /w/). Here are some examples:

Example

ia → hacia → /a.sja/ (LatAm) /a.θja/ (Sp.)

toward

ie → tierra → /tje.ra/

land

io → radio → /ra.djo/

radio

ua → cuadro → /kwa.ðɾo/

square

ue → puerta → /pweɾ.ta/

door

uo → antiguo → /an.ti.ɡwo/

old

Falling Diphthongs

When a strong vowel (/a/, /e/, or /o/) is followed by a weak vowel (/i/ or /u/), the result is a falling diphthong. Here are some examples of falling diphthongs in Spanish:

Example

ai → aire → /ai.ɾe/

air

au → causa → /kau.sa/

cause

ei → peine → /pei.ne/

comb

eu → deuda → /deu.da/

debt

oi → coincidir → /koin.θi.diɾ/ (Sp.) /koin.si.diɾ/ (LatAm)

coincide

ou (rare) → bou → /bou/

trawler

Homogeneous Diphthongs

When two weak vowels (/i/ and /u/) are used together, a homogeneous diphthong is formed. As you can see in the examples below, the first vowel is typically pronounced as a gliding semi-vowel.

Example

iu → viuda → /bju.da/

widow

ui → ruido → /rwi.do/

noise