A diacritical mark (¨) placed over a vowel to indicate a change in sound, often used in Germanic languages.
In the word 'schön', the umlaut over the 'o' changes its pronunciation.
A vowel sound that is modified by the presence of an umlaut.
The umlaut in 'fünf' alters the sound of the 'u'.
The process of vowel mutation in which a vowel is altered, typically fronted or raised, under the influence of a following sound, especially as described in Germanic historical linguistics.
I-umlaut radically changed the Proto-Germanic vowel system during the early stages of Old English.