Diphtongs represent the sound of two vowels together. In the English language there are 8 different diphtongs.
These are the sounds of diphthongs:
Diphthongs can be formed by clustering different pairs of letters, that is, they do not have an exact written form for each sound.
face, great, safe;
kind, might, nice;
boy, choice, oil;
career, fear, here;
care, there, where;
cure, poor, sure;
low, know, phone;
brown, cow, how;
We use diphthongs to categorise different pronunciations.
Diphthongs can be mislead with digraphs, but the main difference of these two is that diphthongs represent the sounds (of two vowels together) and digraphs represent those letters together, that sometimes end up in a diphthong sound.
External link to Diphthongs exercises (1205).