- a historical change in the sound of a vowel, caused by its assimilation to another vowel or semivowel originally occurring in the next syllable but later sometimes lost; mutation: in English, the differences of vowel in certain singulars and plurals (Ex.: foot—feet, mouse—mice) or in certain causative verbs and the words from which they are derived (Ex.: gold—gild) are due to the effects of umlaut on the second word of each pair
- a vowel resulting from such assimilation
- the diacritical mark (¨) placed over a vowel, esp. in German, to indicate umlaut
Origin of umlaut
Ger, change of sound ( from um, about + laut, sound, akin to loud): coined (1774) by F. G. Klopstock, German poet, but first used in special senses by Jakob Grimm (1819) to modify the sound of (a vowel) or write (a vowel) with an umlaut
