Verb: diphthongise 'dif,thóng,Iz or 'dip,thóng,IzUsage: Brit (N. Amer: diphthongize)- Change from a simple vowel to a diphthong
"This vowel diphthongised in Germanic";
- diphthongize
Derived forms: diphthongised, diphthongises, diphthongising
Type of: change, shift, switch