A diphthong is a sound formed by combining two vowels in a single syllable. The sound begins as one vowel sound and moves towards another. The two most common diphthongs in the English language are the letter combination “oy”/“oi”, as in “boy” or “coin”, and “ow”/ “ou”, as in “cloud” or “cow”. Diphthongs are usually introduced as spelling patterns in the primary grades.

VocabularySpellingCity’s diphthong word list can be paired with the fun phonics word game Sound It Out! for independent practice. The game asks students to match phonemes (sounds) to their corresponding graphemes (letters). In the game, diphthongs are recognized as one phoneme, allowing for ideal concept review.

Diphthongs contain two vowels that form one new sound when combined together.

Diphthongs Examples

“aw”/“au” straw, law, saw, cause, haul, author
“oy”/“oi” toy, boy, coy, coin, noise, oil
“ow”/“ou” cow, now, flower, cloud, house, loud