umlaut

 
Pronunciation: /ˈʊmlaʊt/
Linguistics

noun

  • a mark (¨) used over a vowel, especially in German, to indicate a different vowel quality.
  • [mass noun] the process in Germanic languages by which the quality of a vowel was altered in certain phonetic contexts, resulting for example in the differences between modern German Mann and Männer.

verb

[with object]
  • modify (a form or sound) by using an umlaut: the colour of prothetic vowels, unless umlauted by the next syllable, was that of the laryngeal which was vocalized

Origin:

mid 19th century: from German Umlaut, from um 'about' + Laut 'sound'