Diphthongs: oi, oy, ou, ow

Vowel sounds that glide

A diphthong is a special vowel sound. Your mouth starts in one shape and glides into another, all in one breath. Say boy slowly and feel your lips slide! Today we meet oi, oy, ou and ow.

The oi and oy sound

oi and oy make the same sound: oy!

• Use oy at the end of a word: boy 👦, toy 🧸, joy 😊.
• Use oi in the middle: coin 🪙, soil 🪴, boil ♨️.

Say coin and boy. Hear how they match?

The ou and ow sound

ou and ow can both make the ow sound, like when you bump your toe: ow!

• ou words: cloud ☁️, mouse 🐭, house 🏠.
• ow words: cow 🐄, owl 🦉, town 🏘️.

Say cloud and cow. Same gliding ow sound!

A helpful tip

Where the sound sits in the word gives you a clue:

• End of a word with the 'oy' sound? → usually oy (boy, toy).
• End of a word with the 'ow' sound? → often ow (cow, now).

A little word list

Read these diphthong words out loud:

• coin 🪙
• boy 👦
• toy 🧸
• cloud ☁️
• cow 🐄
• owl 🦉

Play the games below to match the gliding sounds!

When you can read these, glide on to the vowel teams ai, ee and oa and the bright long vowel sounds.