Sound like a Native: How to Pronounce Diphthongs

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Did you know that the majority of what makes up a person’s accent are vowels? In fact, one of the most common problems English language learners have is with English pronunce Diphthongs. If you haven’t already, be sure to check out our other blog posts about how to pronounce different English vowels. 

In this post, we will be focusing on a particular subgroup of vowels called diphthongs and how improving your understanding and pronunciation of them can make a big difference in your competence and confidence in speaking English.

I am willing to bet that anyone, from beginner to advanced English speakers, will learn something new from this! Follow along through the practice exercises as well!



Let’s start with some of the basics. 

Most syllables are made up of a monophthong — which is just a fancy way of saying just one vowel (mono meaning one). Most words are like this, like bit, bat, bet, etc. In fact, even words that are SPELLED with two vowel LETTERS are often actually just one vowel SOUND. For example, even though beat is spelled with two vowel letters, “ea”, the sound is just made up of one vowel sound, the /i/ sound.

However, sometimes one syllable is made up of two vowel sounds combined together. These are called diphthongs — (di meaning two). 

There are five major diphthongs in North American English, and they are as follows:

  1. eɪ (cake, eight)
  2. oʊ (boat, rope)
  3. aɪ (hi, bite, right)
  4. aʊ (wow, about)
  5. ɔɪ (boy, avoid)

We are going to discuss some of the more common mistakes made by English language learners with these diphthong sounds and, more importantly, how to fix them!



Let’s start with the two sounds that I think will make the biggest difference for the vast majority of my students, regardless of what language you speak, and regardless of if you are a beginner or advanced: eɪ and oʊ

#1: eɪ (cake, eight, pay)

This vowel in many other languages is pronounced as simply /e/, but in English, it is almost always a diphthong /eɪ/. You can almost think of it having a little “y” or “i” at the end.

We do this by starting with a central front /e/ vowel, then transitioning to a high /ɪ/ vowel.

For Spanish speakers, words like “snake”, “late”, and “face” are pronounced like /snek/, /let/, and /fes/.

Practice saying these words, starting the vowel from a mid jaw position /e/ and transitioning to high jaw vowel /ɪ/. It can help to start off by slowly transitioning the vowels and then picking up the speed as you become more confident!

  1. A (the letter name): /e–ɪ/
  2. snake: /sne–ɪk/
  3. late: /le–ɪt/
  4. face: /fe–ɪs/

#2: oʊ (boat, rope)

A similar thing happens with /oʊ/, which is often reduced to /o/. This diphthong starts with a mid jaw height /o/ vowel, then moves up to a high jaw height /ʊ/ vowel. 

For our Spanish readers, think of the most stereotypical American accent imaginable when trying to say Spanish words, and you will notice the difference. 

Take a word like “peso”. In Spanish, you pronounce the “e” and “o” as monophthongs. When Americans who are new to Spanish try saying this word, they carry the English pattern of making the “e” and “o” into diphthongs. How do English speakers new to Spanish often pronounce “peso”? Something like “pay-sow”, right?

If you manage to incorporate this trick into your English, it will do wonders for how natural your pronunciation sounds!

Practice saying these words, starting the vowel from a mid jaw position /o/ and transitioning to high jaw vowel /ʊ/.

  1. oh: /o–ʊ/
  2. boat: /bo–ʊt/
  3. rope: /ro–ʊp/

#3: /aɪ/ (hi, bite, right)

This sound is made by combining an /a/, which is a low sound, with /ɪ/, which is a high front vowel. 

This diphthong can often be tricky for students when followed by a consonant, particularly for some students from Asian countries like China and Thailand. A common error in some of these languages is reducing the diphthong to just /a/, so that words like “time” become /tam/, where the diphthong /aɪ/ is reduced to the monophthong /a/. 

Practice saying these words, starting the vowel from a low jaw position /a/ and transitioning to high jaw vowel /ɪ/.

  1. eye: /a–ɪ/
  2. I’m: /a–ɪm/
  3. time: /ta–ɪm/

#4: aʊ (wow, about)

This diphthong is heard in words like “how”, “down”, and “around”. Like /aɪ/, it starts with the lower /a/ vowel, but then transitions to the high back vowel /ʊ/.

Also, like /aɪ/, this diphthong is often reduced to a single monophthong vowel depending on what language you speak.

Practice saying these words, starting the vowel from a low jaw position /a/ and transitioning to high jaw vowel /ʊ/.

  1. ow: /a–ʊ/
  2. how: /ha–ʊ/
  3. down: /da–ʊn/
  4. around: /ə.’ra–ʊnd/

#5: ɔɪ (boy, avoid)

Last but not least, for #5, we have /ɔɪ/, which is found in words like “boy”, and “point”. 

The key thing to remember for this /ɔɪ/ sound is that you start with /ɔ/ from a mid jaw position and the lips are slightly, but not overly rounded. You then move up to a high jaw position for the /ɪ/.

Practice saying these words, starting the vowel from a mid jaw position and slightly rounded lips /ɔ/ and transitioning to high jaw vowel /ɪ/. 

  1. oy: /ɔ–ɪ/
  2. boy: /bɔ–ɪ/
  3. point: /pɔ–ɪnt/ 


That concludes today’s lesson! Hopefully, it was helpful for you, and you come away with more knowledge about English vowels and diphthongs. If you have any questions, you can ask in the comments below. If you liked this lesson and want to continue to improve your pronunciation, check out this post about 3 English Vowel Sounds for Better Pronunciation!

See you next time!



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