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The letter O as a diphthong | Better pronunciation

Here’s a photo of the Golden Gate Bridge in San Francisco.

There’s a lot going on around the letter O in English pronunciation! If you are interested in fine-tuning your accent, then listen to this post. You can practise at the end, and there’s a free PDF for you to download.

Here you can listen to the first part.

The sentence in the caption contains the words photo, golden and Francisco. Do you usually pronounce the Os in these as diphthongs? Chances are that you don’t. But let’s take a closer look. (And it may or may not be a coincidence that this post was published on 31 October…)

We’re going to focus on words in which O is pronounced just the way it sounds in the alphabet: əʊ.
The diphthong əʊ can be spelt in several ways; in this post we will only look at the letter O on its own.

What words contain O as a diphthong?

In general terms, O is often pronounced the way it sounds in the alphabet

  • when it is stressed,
  • at the end of a syllable, or
  • at the end of a word.

We can roughly group these words into three categories.

  1. Let’s begin with high-frequency words like verbs, adjectives and adverbs. Many of these words only have one syllable, which means that the O is stressed.
    We use these a lot in everyday language: for example go and no, open and close, only, over, home…
    An important group inside this category are irregular verbs: broken and spoken, sold and told, and so on.
  2. The second group is made up of international wordsThis category offers great examples for əʊ at the end of a syllable.
    Many of these are related to travel, technology or the internet and are used worldwide. For instance hotel, local, mobilerobot.
    In the same category we find universally known names of people, places or brands, for instance Antonio, Pokémon, Oman, Coca Cola™.
  3. The third group of words are those finishing in -o.
    And I have some great news for you: at last we’ve got a simple pronunciation rule. Yay! 😃

    At the end of a word, O is always pronounced as a diphthong.


    Think of words like bravo, Euro, flamingo or photo.
    You will find words and names from Greek, Latin, Italian and Spanish, such as echo, cello, Pinocchio, Picasso.
    Science, music and the arts contain a lot of these words.

Many languages use words from the second and third group but do not necessarily pronounce them with diphthongs. At least in German, which is my mother tongue, and in Spanish, which is spoken where I live, there are definitely no əʊ sounds in them!

Listen here for the second part.

How to pronounce əʊ

əʊ is a combination of two short vowel sounds. We call this a diphthong. The two separate sounds in əʊ are ə, and ʊ.

  1. ə – called the schwa – is a short, neutral sound. To form it, open your mouth a little, relax your lips and quickly let some air out; the position of the tongue is neither high nor low in your mouth: ə.
  2. Now round your lips loosely to produce the second short sound. Keep your tongue relaxed and bring it up slightly towards the back: ʊ.
  3. To begin pronouncing the diphthong, say the two sounds one after the other: əʊ. Now connect them into one longer sound, changing the position of your lips and tongue: əʊ.
  4. And practise! It’s like taking your mouth to the gym. Give the muscles in and around your mouth time to get used to the new movements.
    And give yourself time to get used to the new sound!

How do I really know when O is a diphthong?

The answer is: Listen, and listen carefully. Pay attention to how native speakers pronounce. Be aware of specific sounds and imitate what you hear. (You could start by noticing all the əʊ sounds in this post, for example.)

If you are not sure, check with an online or printed dictionary, where you can listen to words or look at their phonetic transcription.

And lastly, don’t forget: At the end of a word, O is always pronounced as a diphthong.

But why should I pronounce O this way?

You don’t have to, of course.

Some of my students seem to feel embarrassed to use əʊ, thinking it may sound exaggerated or ridiculous. That’s definitely not the case. Bear in mind that English has 20 different vowel sounds alone, and əʊ is one of them.

There are good reasons for making an effort to improve your pronunciation. This recent post explains in depth why good pronunciation makes life easier for everyone.

So start getting rid of bad old habits and begin to sound more authentic by working with the next audio.

Here you can listen to the third part of the post.

Now practise!

Pause the audio after each sentence and imitate what you heard. I speak standard British English. 

  1. Here’s a photo of the Golden Gate Bridge in San Francisco.
  2. It’s cold! Let’s go home and watch a video on the sofa.
  3. Oh no! Don’t you notice the smoke?
  4. I told you so a moment ago. O_diphthong_ghost
  5. We stayed at one of Tokyo‘s oldest hotels.
  6. The new radio station opened last October.
  7. In November he’s giving a piano concert in Mexico.
  8. She sold her phone for 100 Euros.
  9. Will robots control the world one day?
  10. A lot of organisations focus on social issues.
  11. NATO plays a global role in conflict prevention.
  12. We only use fresh, locally grown products.
  13. Mario dressed up as a ghost on Halloween.
  14. Lola‘s car broke down on the toll road.
  15. Nobody spoke; it was totally silent as we drove down the motorway.

I have made a wordlist with many more words containing O as a diphthong. You can download it as a free PDF. O_Dipthong_Wordlist

I recommend that you also read my post on another, interesting way to pronounce the letter O.

Does your language contain a lot of these words? How do you pronounce the O in those words in your language?
What words with an əʊ sound did you find in this post that aren’t listed on the PDF? Please let me know.


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