Definition of: diphthongize

(dif′thông·īz, -thong-, dip′-) v. ·ized, ·iz·ing v.t.
1. To make a diphthong of; combine with another sound in a diphthong.
2. To pronounce as a diphthong.
—v.i.
3. To become a diphthong.
—diph′thong·i·za′tion, diph′thong·a′tion noun