LumiraWhat is a diphthong?
A diphthong is a vowel sound that glides from one position to another inside a single syllable — your mouth moves as you say it. They are best taught as one unit rather than as two separate vowel sounds.
The oi diphthong — word list
Every word below appears in the decodable book on this page, so a reader who practises the list will meet the same words again in context.
- boil
- coil
- coin
- foil
- join
- moist
- oil
- point
- soil
- spoil
- toil
Free decodable book: Decodable Diphthong OI
This is an original Lumira decodable reader, written so that a child can sound out nearly every word using patterns they have already been taught. The full text is below — read it here, or open it in the app to read it together with the words highlighting as you speak.
Mia had a coin. Leo had a coin too. They like it.
Leo can point. Mia can point too. Mia and Leo can point.
Mia and Leo did not spoil the soil. The soil is moist.
Leo can boil an egg. Mia can boil an egg too.
Mia and Leo join at the top. They join and join.
Coin boil soil point join oil coil spoil moist toil foil.
How to teach it
- Say the sound on its own first, several times, before showing any letters.
- Show the spelling and name it explicitly — tell the reader what it says rather than asking them to work it out.
- Blend two or three words from the list together, out loud, slowly.
- Read the decodable book above, where the pattern repeats in real sentences.
- Come back to it two or three days later. Cumulative review is what makes it stick.
Lessons that practise this pattern
oi diphthong
Read oi as in coin and point
Word sort: oi vs oy
Sort words by whether oi appears mid-word or oy appears at the end
Diphthong review: oi, oy, ou, ow
Mixed review of every diphthong spelling taught so far