Editing Germanic umlaut (section)

==== I-mutation in Dutch ====
Late Old Dutch saw a merger of {{IPA|/u/}} and {{IPA|/o/}}, causing their umlauted results to merge as well, giving {{IPA|/ʏ/}}. The lengthening in open syllables in early Middle Dutch then lengthened and lowered this short {{IPA|/ʏ/}} to long {{IPA|/øː/}} (spelled {{angbr|eu}}) in some words. This is parallel to the lowering of {{IPA|/i/}} in open syllables to {{IPA|/eː/}}, as in {{lang|nl|schip}} ("ship") – {{lang|nl|schepen}} ("ships").

In general, the effects of the Germanic umlaut in plural formation are limited.{{sfnp |Howell |Salmons |1997 |p=93}} One of the defining phonological features of Dutch, is the general absence of the I-mutation or secondary umlaut when dealing with long vowels. Unlike English and German, Dutch does not palatalize the long vowels, which are notably absent from the language.{{sfnp |Willemyns |2013 |p=36}} Thus, for example, where modern German has {{lang|de|fühlen}} {{IPA|/ˈfyːlən/}} and English has ''feel'' {{IPA|/fiːl/}} (from Proto-Germanic {{lang|gem-x-proto|fōlijaną}}), standard Dutch retains a back vowel in the stem in {{lang|nl|voelen}} {{IPA|/ˈvulə(n)/}}. Thus, only two of the original Germanic vowels were affected by umlaut at all in Dutch: {{IPA|/a/}}, which became {{IPA|/ɛ/}}, and {{IPA|/u/}}, which became {{IPA|/ʏ/}} (spelled {{angbr|u}}). As a result of this relatively sparse occurrence of umlaut, standard Dutch does not use umlaut as a grammatical marker. An exception is the noun {{lang|nl|stad}} "city" which has the irregular umlauted plural {{lang|nl|steden}}.

Later developments in Middle Dutch show that long vowels and diphthongs were not affected by umlaut in the more western dialects, including those in western [[Province of Brabant|Brabant]] and [[Holland]] that were most influential for standard Dutch. However in what is traditionally called the ''Cologne Expansion'' (the spread of certain [[Central Franconian languages|West German features]] in the south-easternmost Dutch dialects during the High Medieval period) the more eastern and southeastern dialects of Dutch, including easternmost Brabantian and all of [[Limburgish language|Limburgish]] have umlaut of long vowels (or in case of Limburgish, all rounded back vowels), however.{{sfnp |Belemans |Keulen |2004 |pp=22–25 }} Consequently, these dialects also make grammatical use of umlaut to form plurals and diminutives, much as most other modern Germanic languages do. Compare {{lang|nl|vulen}} {{IPA|/vylə(n)/}} and {{lang|nl|menneke}} "little man" from {{lang|nl|man}}.