Diphthong' means *two* *sounds*. It's the term used to describe two vowel sounds that are pronounced closely together in the same syllable. Take the English word 'pain' for example. It's not pronounced 'pa-in', but 'pain'. Or the word 'foul'. It's not 'fo-ul', but 'foul'. Notice the difference? You can think of diphthongs as gliding from one vowel to the next very quickly. Diphthongs therefore, begin one way and end in another.;