What on earth is a diphthong, you ask?
Put simply it’s when two vowels come together side by side and form one syllable, also known as a “gliding vowel”. The one syllable vowel sound is similar to how the two vowels sound on their own, unlike English where a diphthong can sound nothing like the two vowels that make it up. E.g. Cloud.
Here are all the possible diphthongs in Italian. Click to hear their pronunciation.
AI AU EI IA IE IO IU OI UA UE UI UO
Did you notice anything interesting? Both I and U are known as weak vowels, so when they are followed by another vowel, they almost disappear so that I becomes like a ‘y’ sound and U becomes like a ‘w’ sound. These two sounds are known as glides because they “glide” immediately to the next vowel.
Listen to each of the following words and pay particular attention to the diphthongs in each.
Strong Diphthongs: AI, AU, EI, OI
Mai → never
Automatico → automatic (note the difference with the English au-)
Sei → you are
Poi → then, later
Weak ‘gliding’ Diphthongs: IA, IE, IO, IU, UA, UE, UI, UO
Piatto → plate
Ieri → yesterday
Fiore → flower
Più → more
Acqua → water
Questo → this
Guida → guide
Buono → good, nice
There are often words that contain both types of diphthongs:
Australia → Australia (written the same, NOT pronounced the same!)
Diphthongs, as with all Italian vowels, are particularly important to pronounce correctly. If you pronounce a diphthong or any Italian vowel as you would in English, then chances are that most Italians would struggle to understand you.
That’s why it’s so important to practice good Italian pronunciation skills right from the start!