diphthongize

listen to the pronunciation of diphthongize
English - English
To become a diphthong
To change to a diphthong (as by inserting or removing a vowel)
To change into a diphthong, as by affixing another vowel to a simple vowel
change from a simple vowel to a diphthong; "This vowel diphthongized in Germanic
{f} (Grammar) change from a simple vowel to a diphthong (also diphthongise)
diphthongization
The act of changing into a diphthong
diphthongization
{i} act of changing into a diphthong; pronounce as a diphthong (also diphthongisation)