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