0 a mark put over a vowel in some languages, such as German, to show that the pronunciation of the vowel is changed:
An elegant featural statement of umlaut phonology may well be possible, but it is not our concern here.
Lengthening is a change in the length feature (and\or the tense feature) whilst umlaut fronts back vowels.
There is also a minor subclass which has a stem alternation other than umlaut.
In contrast, umlaut is neither a separate segment nor stem final and is thus less salient.
All of the former are reconstructed as having had a suffix containing a 'high front unround' segment which 'triggered' the umlaut reflected in these spellings.
The same applies to the morphophonological alternations vowel lengthening and umlaut, which are discussed in sections 4.1 and 4.2 below.
The realization of umlaut is more complex than a fronting of back vowels.
An anonymous reviewer points out that it has been argued that 'vowel harmony is demarcative, while umlaut is compensatory'.
