A diphthong is a vowel sound that moves. Your mouth starts in one position and glides to another, all inside one syllable. Say day slowly and you can feel it: it is not a flat “e”, it ends with a small “ee”. Vowels that do not move, like the /iː/ in sheep, are called monophthongs.
British English has eight diphthongs. They are easy to remember in three groups, according to where the glide ends.
All eight diphthongs
| Sound | Glide | Examples | Common spellings |
|---|---|---|---|
| /eɪ/ | from /e/ to /ɪ/ | day, may, make, wait, waiter, maid, raise, rain, faith, eight, great, they | a_e, ai, ay, eigh, ey, ea |
| /aɪ/ | from /a/ to /ɪ/ | time, smile, my, mine, die, dye, lie, tie, high, nigh, buy, guy, eye | i_e, y, ie, ye, igh, uy, eye |
| /ɔɪ/ | from /ɔ/ to /ɪ/ | boy, coin, enjoy, voice, toy, noise | oy, oi |
| /əʊ/ (US /oʊ/) | from /ə/ to /ʊ/ | go, home, boat, know, slow, though | o, o_e, oa, ow, oe, ough |
| /aʊ/ | from /a/ to /ʊ/ | now, house, loud, brown, out, down | ow, ou |
| /ɪə/ (US /ɪr/) | from /ɪ/ to /ə/ | here, near, beer, idea, ear, weird | ere, ear, eer, ea |
| /eə/ (US /er/) | from /e/ to /ə/ | hair, there, care, square, wear, bear | air, ere, are, ear |
| /ʊə/ (US /ʊr/) | from /ʊ/ to /ə/ | tour, pure, cure, poor, sure, Europe | ure, oor, our |
Three groups
- Gliding up to /ɪ/ (the mouth closes a little, the tongue moves forward): /eɪ/ /aɪ/ /ɔɪ/.
- Gliding up to /ʊ/ (the lips round): /əʊ/ /aʊ/.
- Gliding to the schwa /ə/ (the mouth relaxes, they are called centring diphthongs): /ɪə/ /eə/ /ʊə/.
How to say them well
- Start clearly, end lightly. The first part is the strong part. The second part is short and soft. Time is not “tie-eem”.
- Do not cut the glide. A common mistake is to say go as a flat “goh” and day as a flat “deh”. Let the mouth move.
- Use a mirror. For /aɪ/ and /aʊ/ your jaw starts wide open and closes. For /əʊ/ and /aʊ/ your lips end rounded.
- Hold only the first part. If you want to practise, stretch the beginning (aaaaaaee) and then say the word at normal speed.
Practice
Drag each word to the diphthong it has. The spelling can mislead you: great, though and eye are good examples.
Words to sort: day, make, rain, eight, great, they, time, high, buy, eye, tie, my, go, home, boat, know, slow, though. Three groups: /eɪ/ as in day; /aɪ/ as in time; /əʊ/ as in go.
Choose the diphthong in each word (British pronunciation).
Press 🔊, listen to the sound, and choose the diphthong you heard. Press it again to hear it again. Each time you start, the sounds are different.