"Diphthongise" Natural Recordings by Native Speakers
To diphthongise means to pronounce a vowel sound as a combination of two vowel sounds, with the sound changing smoothly from one to the other. For example, the "ou" in English words like "noise" or "boat" is a diphthong.
Diphthongising is the act of pronouncing a vowel sound as if it were a combination of two distinct vowel sounds, typically a glide from one vowel to another, often used in linguistics and phonetics to describe the process of changing a single vowel sound into a diphthong.