juhivõnnu
Juhivõnnu refers to a phenomenon in Estonian linguistics related to vowel harmony, specifically within the context of diphthongs. In Estonian, vowel harmony generally dictates that vowels within a single word should belong to a certain class. While Estonian is not a strict vowel harmony language like Finnish, certain phonological rules and tendencies exist. Juhivõnnu specifically addresses how diphthongs, which are a sequence of two vowel sounds in the same syllable, behave in relation to the vowel harmony system.
The term itself is derived from Estonian words "juhi" (leader or guiding) and "vönnu" (a colloquial or