diphthongize

verb

diph·​thong·​ize ˈdif-ˌthȯŋ-ˌīz 

ˈdip-

diphthongized; diphthongizing

intransitive verb

of a simple vowel : to change into a diphthong

transitive verb

: to pronounce as a diphthong

diphthongization

(ˌ)dif-ˌthȯŋ-ə-ˈzā-shən 

(ˌ)dip-

noun

Word History

First Known Use

1867, in the meaning defined at intransitive sense