diphtonguer betyder på engelska

diphthongize [diphthongized, diphthongizing, diphthongizes]▼◼◼◼(to become a diphthong)
verb
[UK: ˈdɪf.θɒŋ.ɡaɪz] [US: ˈdɪf.θɔːŋ.ˌaɪz]