Diphthongs (Gliding Vowels)

Intermediate · Vowel Sounds

A diphthong is two vowel sounds joined in one syllable — your mouth glides from one position to another. Say "I" slowly and you can feel it move from "ah" to "ee" (/aɪ/). English has about eight of these gliding vowels.

The key is to actually make the glide (the movement), not a single flat vowel. Many learners flatten "no" (/nəʊ/) into a plain "o", which sounds foreign.

Common diphthongs

/eɪ/ day · /aɪ/ my · /ɔɪ/ boy · /aʊ/ now · /əʊ/ go (UK) · /ɪə/ here

Rules & examples

  1. /eɪ/ as in "day" — glide from "e" to "i".

    A smooth movement, not a flat "eh".

    • day, make, rain, eight, they
  2. /aɪ/ as in "my" — glide from "ah" to "ee".

    The name of the letter "I".

    • my, time, high, buy, eye
  3. /əʊ/ (UK) or /oʊ/ (US) as in "go" — glide from schwa/"o" toward "oo".

    Let the lips round as you finish.

    • go, no, home, boat, know
  4. /aʊ/ as in "now" — glide from "ah" to "oo".

    A wide-to-round movement.

    • now, house, out, down, town

Minimal pairs

  • so / saw — diphthong /əʊ/ vs single long /ɔː/
  • day / die — /eɪ/ vs /aɪ/
  • no / now — /əʊ/ vs /aʊ/

Tips to remember

  • Make the glide audible — your mouth should visibly move from the first shape to the second.
  • Do not add an extra syllable; a diphthong is still ONE syllable, just a moving one.