I-mutation

I-mutation (also known as umlaut, front mutation, i-umlaut, i/j-mutation or i/j-umlaut) is a type of sound change in which a back vowel is fronted, or a front vowel is raised, if the following syllable contains /i/, /ī/ or /j/ (a voiced palatal approximant, sometimes called yod, the sound of English <y> in yes). It is a category of regressive metaphony, or vowel harmony.

The term is usually used by scholars of the Germanic languages: i-mutation is particularly important in the history of the Germanic languages because inflectional suffixes containing an /i/ or /j/ led to many vowel alternations that are important in the morphology of these languages today: see Germanic umlaut.

The terms i-mutation and i-umlaut are usually applied to processes in the early Germanic languages. The phenomenon exists in many other languages, but is often referred to by different names. It is still productive in some Romance languages including Central Venetian whose final -i is still pronounced: te parchigi < */parchégi/ "you park your car" vs. parchégio "I park". However, i-mutation in the Romance languages is more commonly called metaphony (from Ancient Greek, meaning "process of changing sounds", of which German umlaut is a translation). Meanwhile, in the Celtic languages, it is referred to as affection.

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