Simple Diphthongs (two vowel sounds smoothly transitioning into each other):
* oi as in "boy," "coin," "toy"
* ou as in "out," "house," "mouse"
* ow as in "now," "cow," "how"
* ay as in "say," "play," "day"
* ey as in "they," "grey," "prey"
* ie as in "pie," "tie," "lie"
* ue as in "blue," "true," "glue"
More Complex Diphthongs (often with a vowel sound that shifts to a glide):
* au as in "caught," "taught," "thought"
* aw as in "saw," "raw," "law"
* ew as in "few," "new," "dew"
* oo as in "moon," "food," "soon"
Note:
* Diphthongs are represented by two letters in the spelling, but they are pronounced as a single, gliding sound.
* The sound of a diphthong can vary slightly depending on the surrounding sounds and accents.
Let me know if you'd like to explore specific examples or learn more about how diphthongs work!