diphthongization
Noun
Meaning
The act of changing into a diphthong.
Source: Webster's dictionaryExamples
Among the phonological processes operating in Finnish dialects are diphthongization and diphthong reduction.
Hawaiian phonological processes include palatalization and deletion of consonants, as well as raising, diphthongization, deletion, and compensatory lengthening of vowels.
However, they are viewed negatively, and their frequency is higher among uneducated speakers, Ostiguy, pp. 93-95 although Québécois teachers generally use the diphthongization.
Vowel breaking or diphthongization is a vowel shift in which a monophthong becomes a diphthong.