A is one sound that glides from one position to another within a single , as in say, go and price. British English has eight: , , , , , , and . The first part is stronger and longer, and the second part is short and light.
What is a diphthong?
Short and long are pure vowels: the tongue stays still. A is different. The tongue and lips start in one place and move towards another while you say the sound. It is one , not two.
Say the word 'go' very slowly. You can feel your lips move from a middle shape to a small round shape. Now say 'say'. Your tongue moves up and forward. If you hold a pure vowel and do not move, you do not make a diphthong.
The eight British English diphthongs
There are two groups. The first five end in a closing movement towards or . The last three end in a movement towards the weak and are called centring .
- as in face: say, day, wait, eight
- as in price: time, my, high, buy
- as in choice: boy, enjoy, noise, toy
- as in goat: go, home, know, phone
- as in mouth: now, house, town, down
- as in near: here, idea, year, clear
- as in square: there, care, air, share
- as in cure: tour, pure, sure (said /ʃɔː/ by many speakers)
How the glide works
In each , the first part is the strong part. It is longer and louder. The second part is short and light, and it often does not reach the target position. So is not a clear 'ah' then a clear 'ee'. It is a strong 'ah' that slides a short way up.
For , start with an open mouth and glide up towards . For , start open and glide up with lips rounding towards . For , start with a relaxed middle and glide to a small round lip shape. For , start with and glide upwards. For , start with a rounded and glide to .
The centring diphthongs
The three centring finish with . is in here, near and idea. is in there, care and share. is in tour and pure, but it is becoming rare. Many British speakers now say in words like sure, and some say /tɔː/ for tour. So you may use in sure and sound quite natural.
In words such as fire and hour, many speakers shorten the sound to a single . You can say them as one syllable, /faɪə/ and /aʊə/, with a quick glide at the end.
Common mistakes
The most common mistake is replacing a with a pure . Learners say 'go' as /ɡo/ and 'say' as /se/. In British English, these have a glide, and the pure vowel can sound foreign. The reverse also happens: some learners add a long, clear second part and make two , so that 'my' sounds like 'my-ee'.
Another mistake is mixing close pairs. Bet and bait, cot and coat, and bit and bite are different words. A listener who hears a diphthong where you meant a short vowel, or the opposite, will hear a different word. Pair practice helps here.
How to practise
Move slowly at first. Say each as a continuous slide, and watch your mouth in a mirror. Then say the key word. Next say pairs that contrast a short and a diphthong: bet and bait, cot and coat, pen and pain, hat and height. Finish with short phrases such as 'a nice day', 'go home', 'a noisy town' and 'near here'.
Record yourself. Listen for a smooth slide inside the . If you hear two separate vowels, you are going too slowly. If you hear one flat vowel, add the glide.
How to make the sound
- Start the in the first position, with a clear, strong sound.
- Move your tongue and lips smoothly towards the second position while the sound continues.
- Make the second part short and light, and keep it all in one .
- Say price, mouth and goat slowly, then at normal speed, and watch your mouth in a mirror.
Who finds this hard?
- Spanish speakers: Spanish e and o are pure , so learners often say 'say' as /se/ and 'go' as /ɡo/. Practise the glide at the end of face, day, go and home.
- Italian speakers: Italian e and o are also pure vowels, so say and go may sound too short and flat. Add a clear glide to the end of the sound.
- Japanese speakers: Japanese learners often use a pure vowel in say and go and may add an extra vowel after a . Keep the glide inside one .
IELTS tip
In the Speaking test, fill many of the most common words: my, now, go, make, home, time and know. A clear glide makes these words easier to recognise. Practise a short answer that includes ten diphthong words, and record it to check that each one slides and stays in one .
Frequently asked questions
What is a diphthong?
It is a sound that glides from one vowel position to another within one , as in price, go and mouth.
How many diphthongs are there in English?
In British English there are eight: , , , , , , and . Some speakers use instead of in some words.
Is a diphthong two vowels?
It is written with two symbols, but it is one sound and one syllable. The two parts blend into a single glide.
Do all English accents have the same diphthongs?
No. Accents differ. In this course we use standard British English, and in some other accents the sounds in words like face and goat are pure vowels.
Sources
- Roach, P. (2009). English Phonetics and Phonology: A Practical Course (4th ed.). Cambridge University Press.
- Cruttenden, A. (2014). Gimson's Pronunciation of English (8th ed.). Routledge.