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v. Present participle of diphthongize.

"Each table illustrates the tendency to reduction of unaccented syllables, the vocalic modification of the radical element under the influence of the following vowel, the rise in tongue position of the long middle vowels (English o to u, e to i; German o to uo to u, üe to ü), the diphthongizing of the old high vowels (English i to ei to ai; English and German u to ou to au; German ü to öü to oi)."

diphthongized    diphthongizing   

change    switch    shift   

monophthongize   

break