umlaut (process)
Definition - A process in which a vowel at a word’s end changes the vowels that precede it, because speakers pre-shape their mouths to anticipate the ending vowel.

1. German vowels that have undergone this process are marked with dieresis, e.g. ä, ö, and ü.

Example -
In early Germanic languages, the plural of man was mani. Because speakers anticipated the i, they tended to pronounce it as meni instead of mani. Eventually, when the i was dropped, the result was that the plural of man became men.

Etymology -
The word means "change of sound" in German (from um, about + laut, sound). It was coined in 1774 by Friedrich Gottlieb Klopstock (1724-1803), but it was first used in its current linguistic sense by Jacob Grimm.

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