Editing Germanic umlaut (section)

== Morphological effects ==

Although umlaut was not a grammatical process, umlauted vowels often serve to distinguish grammatical forms (and thus show similarities to ablaut when viewed synchronically), as can be seen in the English word ''man''. In ancient Germanic, it and some other words had the plural suffix {{lang|gem-x-proto|-iz}}, with the same vowel as the singular. As it contained an {{lang|gem-x-proto|i}}, this suffix caused fronting of the vowel and, when the suffix later disappeared, the mutated vowel remained as the only plural marker: ''men''. In English, such plurals are rare: ''man, woman, tooth, goose, foot, mouse, louse, brother'' (archaic or specialized plural in ''brethren''), and ''cow'' (poetic and dialectal plural in ''kine''). This effect also can be found in a few fossilized [[diminutive]] forms, such as ''kitten'' from ''cat'', ''kernel'' from ''corn'', and the feminine ''vixen'' from ''fox''. Umlaut is conspicuous when it occurs in one of such a pair of forms, but there are many mutated words without an unmutated parallel form. Germanic actively derived [[Germanic weak verb#Causative verbs|causative weak verbs]] from ordinary [[Germanic strong verb|strong verbs]] by applying a suffix, which later caused umlaut, to a past tense form. Some of these survived into modern English as doublets of verbs, including ''fell'' and ''set'' versus ''fall'' and ''sit''. Umlaut could occur in borrowings as well if a stressed vowel was coloured by a subsequent front vowel, such as German {{lang|de|Köln}}, "[[Cologne]]", from Latin {{lang|la|Colonia}}, or {{lang|de|Käse}}, "cheese", from Latin {{lang|la|caseus}}.

===Parallel umlauts in some modern Germanic languages===

{| class="wikitable"
!'''Germanic'''
!'''German'''
!'''English'''
!'''Dutch'''
!'''Limburgish'''
!'''Swedish'''
!'''Faroese'''
|-
| {{lang|gem-x-proto|*fallaną}} – {{lang|gem-x-proto|*fallijaną}}
| {{lang|de|fallen}} – {{lang|de|fällen}}
| ''to fall'' – ''to fell''
| {{lang|nl|vallen}} – {{lang|nl|vellen}}
| {{lang|li|valle}} – {{lang|li|velle}}
| {{lang|sv|falla}} – {{lang|sv|fälla}}
| {{lang|fo|falla}} – {{lang|fo|fella}}
|-
| {{lang|gem-x-proto|*fōts}} – {{lang|gem-x-proto|*fōtiz}}
| {{lang|de|Fuß}} – {{lang|de|Füße}}
| ''foot'' – ''feet''
| {{lang|nl|voet}} – {{lang|nl|voeten}} (no umlaut)
| {{lang|li|voot}} – {{lang|li|veut}}
| {{lang|sv|fot}} – {{lang|sv|fötter}}
| {{lang|fo|fótur}} – {{lang|fo|føtur}}
|-
| {{lang|gem-x-proto|*aldaz}} – {{lang|gem-x-proto|*alþizô}} – {{lang|gem-x-proto|*alþistaz}}
| {{lang|de|alt}} – {{lang|de|älter}} – {{lang|de|am ältesten}}
| ''old'' – ''elder'' – ''eldest''
| {{lang|nl|oud}} – {{lang|nl|ouder}} – {{lang|nl|oudst}} (no umlaut)
| {{lang|li|aad}} – {{lang|li|ajer}} – {{lang|li|aadjst}} (no umlaut)
| {{lang|sv|gammal}} – {{lang|sv|äldre}} – {{lang|sv|äldst}} (irregular)
| {{lang|fo|gamal}} – {{lang|fo|eldri}} – {{lang|fo|elstur}} (irregular)
|-
| {{lang|gem-x-proto|*fullaz}} – {{lang|gem-x-proto|*fullijaną}}
| {{lang|de|voll}} – {{lang|de|füllen}}
| ''full'' – ''fill''
| {{lang|nl|vol}} – {{lang|nl|vullen}}
| {{lang|li|vol}} – {{lang|li|völle}}
| {{lang|sv|full}} – {{lang|sv|fylla}}
| {{lang|fo|fullur}} – {{lang|fo|fylla}}
|-
| {{lang|gem-x-proto|*langaz}} – {{lang|gem-x-proto|*langīn/*langiþō}}
| {{lang|de|lang}} – {{lang|de|Länge}}
| ''long'' – ''length''
| {{lang|nl|lang}} – {{lang|nl|lengte}}
| {{lang|li|lank}} – {{lang|li|lengde}}
| {{lang|sv|lång}} – {{lang|sv|längd}}
| {{lang|fo|langur}} – {{lang|fo|longd}}
|-
| {{lang|gem-x-proto|*lūs}} – {{lang|gem-x-proto|*lūsiz}}
| {{lang|de|Laus}} – {{lang|de|Läuse}}
| ''louse'' – ''lice''
| {{lang|nl|luis}} – {{lang|nl|luizen}} (no umlaut)
| {{lang|li|loes}} – {{lang|li|luus}}
| {{lang|sv|lus}} – {{lang|sv|löss}}
| {{lang|fo|lús}} – {{lang|fo|lýs}}
|}

The Standard Dutch pair ''{{lang|nl|luis}}'' – ''{{lang|nl|luizen}}'' differs from the rest in that it already features a front diphthong {{IPA|/œy/}} ({{IPA|/lœys/}} – {{IPA|/ˈlœyzə(n)/}}), which ultimately comes from a long close back monophthong {{IPA|/uː/}}, retained in Limburgish dialects in the singular form. In the Dutch-based orthography usually used to write Limburgish, the digraph {{angbr|eu}} and the double {{angbr|uu}} have the same phonetic values as the long versions of {{angbr|ö}} and {{angbr|ü}} in German, that is {{IPA|/øː/}} and {{IPA|/yː/}}, whereas {{angbr|oe}} is {{IPA|/uː/}}, the back counterpart of {{IPA|/yː/}}.