Definition from Wiktionary, the free dictionary
See also Umlaut
- (UK) IPA: /ˈʊm.laʊt/, /ˈʌm.laʊt/, X-SAMPA: /"Um.laUt/, /"Vm.laUt/
- (US) IPA: /ˈʊm.laʊt/, /ˈum.laʊt/, X-SAMPA: /"Um.laUt/, /"um.laUt/
Audio (US) (file)
- (linguistics) An assimilatory process whereby a vowel is pronounced more like a following vocoid that is separated by one or more consonants.
- (linguistics) The umlaut process (as above) that occurred historically in Germanic languages whereby back vowels became front vowels when followed by syllable containing a front vocoid (e.g. Germanic lūsi > Old English līs(i) > Modern English lice).
- (linguistics) A vowel so assimilated.
- (orthography) The diacritical mark ( ¨ ) placed over a vowel, usually when it indicates such assimilation.
Usage notes 
- Although this symbol has the same form as the diaeresis/dieresis, it has as a different function and so in standard and technical usage these two terms are not interchangeable.
- When spelling a German word out loud, one can say “(vowel) umlaut” or “umlauted (vowel)”. e.g. “oh umlaut” or “umlauted oh” mean “an ‘o’ with an umlaut over it” (ö). (German practice is to pronounce the letters, so the name of "Ä" is [ɛː], just as "A" is [aː] and "B" is [beː].)
- The usual English plural is umlauts, but the form umlaute (after the German) has seen some use. It is quite rare, however.
Derived terms 
partial assimilation of a vowel
- To place an umlaut over a vowel.
See also 
From German Umlaut
- umlaut (assimilation a->ä, o->ö or u->ü in German and some closely related languages)
Declension of umlaut (type risti)