In linguistics, umlaut (from German um- "around"/"the other way" + Laut "sound") is a process whereby a vowel is pronounced more like a following vowel or semivowel. The term umlaut was originally coined and is used principally in connection with the study of the Germanic languages. In Germanic umlaut (also i-umlaut or i-mutation), a back vowel changes to the associated front vowel or a front vowel becomes closer to /i/ when the following syllable contains /i/, /iː/, or /j/. This process took place separately in the various Germanic languages starting around 450 or 500 AD, and affected all of the early languages except for Gothic. An example of the resulting vowel change is the English plural foot > feet.
Umlaut should be clearly distinguished from other historical vowel phenomena such as the earlier Indo-European ablaut (vowel gradation), which is observable in the declension of Germanic strong verbs such as sing/sang/sung.
Umlaut is a form of assimilation, the process by which one speech sound is altered to make it more like another adjacent sound. If a word has two vowels, one far back in the mouth and the other far forward, more effort is required to pronounce the word than if the vowels were closer, and therefore one possible linguistic development is for these two vowels to be drawn closer together.
Germanic umlaut is a specific historical example of this process that took place in the unattested earliest stages of Old English, Old High German, and some other old Germanic languages. Whenever a back vowel (/a/, /o/ or /u/, whether long or short) occurred in a syllable and the front vowel /i/ or the front glide /j/ occurred in the next, the vowel in the first syllable was fronted. So, for example, pre-Old English *mūsi "mice" shifted to *mȳsi, which eventually developed to modern mice, while the singular form *mūs lacked a following /i/ and was unaffected, eventually becoming modern mouse. The fronted variant caused by umlaut was originally allophonic (i.e. a variant sound automatically predictable due to the context), but later became phonemic (a separate sound in its own right) when the context was lost but the variant sound remained. In this case, when final i was lost, the variant sound -ȳ- became a new phoneme in Old English:
|Loss of final -z||West Germanic||*mūs||*mūsi||*fōt||*fōti|
|Germanic umlaut||Pre-Old English||*mūs||*mȳsi||*fōt||*fø̄ti|
|Loss of i after a heavy syllable||Pre-Old English||mūs||mȳs||fōt||fø̄t|
|Unrounding of ø̄ (> ē)||Most Old English dialects||mūs||mȳs||fōt||fēt|
|Unrounding of ȳ (> ī)||Early Middle English||mūs||mīs||fōt||fēt|
|Great Vowel Shift||Early Modern and Modern English||/maʊs/||/maɪs/||/fʊt/||/fiːt/|
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). We can see this in the English word man; in ancient Germanic, the plural of this and some other words had the plural suffix -iz, and the same vowel as the singular. As it contained an 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 umlaut-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). It also can be found in a few fossilized diminutive forms, such as kitten from cat and kernel from corn. 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 causative weak verbs from ordinary 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 vs. fall (older past *fefall) and sit.
Parallel umlauts in some modern Germanic languages
|*fallanan - *fallijanan||fallen - fällen||to fall - to fell||vallen - vellen||falla - fälla||falla - fella|
|*fōts - *fōtiz||Fuß - Füße||foot - feet||voet - voeten (no umlaut)||fot - fötter||fótur - føtur|
|*aldaz - *alþizô - *alþistaz||alt - älter - am ältesten||old - elder - eldest||oud - ouder - oudst (no umlaut)||gammal - äldre - äldst (irregular)||gamal - eldri - elstur (irregular)|
|*fullaz - *fullijanan||voll - füllen||full - to fill||vol - vullen||full - fylla||fullur - fylla|
|*langaz - *langīn/*langiþō||lang - Länge||long - length||lang - lengte||lång - längd||langur - longd|
|*lūs - *lūsiz||Laus - Läuse||louse - lice||luis - luizen (no umlaut)||lus - löss||lús - lýs|
German orthography 
German orthography is generally consistent in its representation of i-umlaut. The umlaut diacritic, consisting of two dots above the vowel, is used for the fronted vowels, making the historical process much more visible in the modern language than is the case in English: a>ä, o>ö, u>ü, au>äu.
Sometimes a word has a vowel affected by i-umlaut, but the vowel is not marked with the umlaut diacritic. Usually the word with an umlauted vowel comes from an original word without umlaut, but the two are not recognized as a pair because the meaning of the umlauted word has changed.
The adjective fertig ("ready", "finished"; originally "ready to go") contains an umlaut mutation, but it is spelled with e rather than ä as its relationship to Fahrt (journey) has for most speakers of the language been lost from sight. Likewise, alt (old) has the comparative älter (older), but the noun from this is spelled Eltern (parents). Aufwand (effort) has the verb aufwenden (to spend, to dedicate) and the adjective aufwendig (requiring effort), though the 1996 spelling reform now permits the alternative spelling aufwändig (but not aufwänden). For denken, see below.
On the other hand, some foreign words have umlaut diacritics that do not mark a vowel produced by the sound change of umlaut. Notable examples are Känguru from English kangaroo, and Büro from French bureau. In the latter case the diacritic is a pure phonological marker, with no regard to etymology; in case of the kangaroo (identical in sound to *Kenguru), it somewhat etymologically marks the fact that the sound is written with an a in English. Similarly, Big Mac can be spelt Big Mäc in German, which even used to be the official spelling used by McDonald's in Germany.
Für "for" is a special case; it is an umlauted form of vor "before", but other historical developments changed the expected ö into ü. In this case, the ü marks a genuine, but irregular umlaut. Other special cases are fünf "five" (expected form *finf) and zwölf "twelve" (expected form *zwälf/zwelf), where the modern umlauted vowel arose from a different process, i.e. rounding an unrounded front vowel (possibly due to the labial consonants w/f occurring on both sides).
False ablaut in verbs 
Two interesting examples of umlaut involve vowel distinctions in Germanic verbs. Often these are subsumed under the heading "ablaut" in descriptions of Germanic verbs, giving them the name false ablaut.
The German word Rückumlaut ("reverse umlaut") is the slightly misleading term given to the vowel distinction between present and past tense forms of certain Germanic weak verbs. Examples in English are think/thought, bring/brought, tell/told, sell/sold. (These verbs have a dental -t or -d as a tense marker, therefore they are weak and the vowel change cannot be conditioned by ablaut.) The presence of umlaut is possibly more obvious in German denken/dachte ("think/thought"), especially if it is remembered that in German the letters <ä> and <e> are usually phonetically equivalent. The Proto-Germanic verb would have been *þankijanan; the /j/ caused umlaut in all the forms that had the suffix; subsequently the /j/ disappeared. The term "reverse umlaut" indicates that if, with traditional grammar, we take the infinitive and present tense as our starting point, there is an illusion of a vowel-shift towards the back of the mouth (so to speak, <ä>→<a>) in the past tense, but of course the historical development was simply umlaut in the present tense forms.
A variety of umlaut occurs in the 2nd- and 3rd-person singular forms of the present tense of some Germanic strong verbs. For example, German fangen ("to catch") has the present tense ich fange, du fängst, er fängt. The verb geben ("give") has the present tense ich gebe, du gibst, er gibt, though the shift e→i would not be a normal result of umlaut in German. There are in fact two distinct phenomena at play here; the first is indeed umlaut as it is best known, but the second is older and occurred already in Proto-Germanic itself. In both cases, a following i triggered a vowel change, but in Proto-Germanic this only affected e. The effect on back vowels did not occur until hundreds of years later, after the Germanic languages had already begun to split up: *fanhanan, *fanhidi with no umlaut of a, but *gebanan, *gibidi with umlaut of e.
West Germanic languages 
Although umlaut operated the same way in all the West Germanic languages, the exact words in which it took place and the outcomes of the process differ between the languages. Of particular note is the loss of word-final -i after heavy syllables. In the more southern languages (Old High German, Old Dutch, Old Saxon), forms that lost -i often show no umlaut, while in the more northern languages (Old English, Old Frisian) they do. Compare Old English ġiest "guest" which shows umlaut, and Old High German gast which doesn't, both from Proto-Germanic *gastiz. This may mean that there was dialectal variation in the timing and spread of the two changes, with final loss happening before umlaut in the south but after it in the north. On the other hand, umlaut may have still been partly allophonic, and the loss of the conditioning sound may have triggered an "un-umlauting" of the preceding vowel. Nevertheless, medial -ij- consistently triggers umlaut, although its subsequent loss is universal in West Germanic except for Old Saxon and early Old High German.
I-mutation in Old English 
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I-mutation is particularly visible in the inflectional and derivational morphology of Old English, since it affected so many of the Old English vowels. Of 16 basic vowels and diphthongs in Old English, only the four vowels ǣ, ē, i, ī were unaffected by i-mutation. Although i-mutation was originally triggered by an /i/ or /j/ in the syllable following the affected vowel, by Old English times the /i/ or /j/ had generally dropped out or been modified (usually to /e/), with the result that i-mutation generally appears as a morphological process that affects a certain (seemingly arbitrary) set of forms. The most common forms affected are:
- The plural, and genitive/dative singular, forms of consonant-declension nouns (original suffix -iz), as compared to the nominative/accusative singular – e.g., fōt "foot", fēt "feet"; mūs "mouse", mȳs "mice". Note that many more words were affected by this change in Old English vs. modern English – e.g., bōc "book", bēc "books"; frēond "friend", frīend "friends".
- The second and third-person present singular indicative of strong verbs (original suffixes -ist, -iþ), as compared to the infinitive and other present-tense forms – e.g. helpan "to help", helpe "(I) help", hilpst "(you sg.) help" (cf. archaic "thou helpest"), hilpþ "(he/she) helps" (cf. archaic "he helpeth"), helpaþ "(we/you pl./they) help".
- The comparative form of some adjectives (original suffixes -ira < -izōN, -ist < -istaz), as compared to the base form – e.g. eald "old", ieldra "older", ieldest "oldest" (cf. "elder, eldest").
- Throughout the first class of weak verbs (original suffix -jan), as compared to the forms from which the verbs were derived – e.g. fōda "food", fēdan "to feed" < *fōdjan; lār "lore", lǣran "to teach"; fiellan "to fell", feallan "to fall".
- In the abstract nouns in þ(u) (original suffix -iþō) corresponding to certain adjectives – e.g., strang "strong", strengþ(u) "strength"; hāl "whole/hale", hǣlþ(u) "health"; fūl "foul", fȳlþ(u) "filth".
- In female forms of several nouns with the suffix -enn (original suffix -injō) – e.g., god "god", gydenn "goddess" (cf. German Gott, Göttin); fox "fox", fyxenn "vixen".
- In i-stem abstract nouns derived from verbs (original suffix -iz) – e.g. cyme "a coming", cuman "to come"; byre "a son (orig., a being born)", beran "to bear"; fiell "a falling", feallan "to fall"; bend "a bond", bindan "to bind". Note that in some cases the abstract noun has a different vowel than the corresponding verb, due to Proto-Indo-European ablaut.
I-mutation affects vowels as follows:
|æ||e||þæc "covering" (cf. "thatch"), þeccan "to cover"|
|e||i||helpan "to help", hilpþ "(he/she) helps"|
|a+m/n||e+m/n||mann "man", menn "men"|
|a||æ, e||bacan "to bake", bæcþ "(he/she) bakes"; talu "tale", tellan "to tell"|
|ā||ǣ||lār "teaching" (cf. "lore"), lǣran "to teach"|
|o||e||dohtor "daughter", dehter "daughters"|
|ō||ē||fōt "foot", fēt "feet"|
|u, o||y||murnan "to mourn", myrnþ "(he/she) mourns"; gold "gold", gyldan "to gild"|
|ū||ȳ||mūs "mouse", mȳs "mice"|
|ea||i.e.||eald "old", ieldra "older" (cf. "elder")|
|ēa||īe||nēah "near" (cf. "nigh"), nīehst "nearest" (cf. "next")|
|eo||i.e.||beornan "to burn", biernþ "(he/she) burns"|
|ēo||īe||sēoþan "to boil" (cf. "seethe"), sīeþþ "(he/she) boils"|
- The phonologically expected umlaut of /a/ is /æ/. However, in many cases /e/ appears. Most /a/ in Old English in fact stem from earlier /æ/ due to a change called a-restoration. This change was blocked when /i/ or /j/ followed, leaving /æ/, which subsequently mutated to /e/. For example, in the case of talu "tale" vs. tellan "to tell", the forms at one point in the early history of Old English were tælu and tælljan, respectively. A-restoration converted tælu to talu, but left tælljan alone, and it subsequently evolved to tellan by i-mutation. The same process "should" have led to *becþ instead of bæcþ. That is, the early forms were bæcan and bæciþ. A-restoration converted bæcan to bacan, but left alone bæciþ, which would normally have evolved by umlaut to *becþ. In this case, however, once a-restoration took effect, bæciþ was modified to baciþ by analogy with bacan, and then later umlauted to bæcþ.
- A similar process resulted in the umlaut of /o/ sometimes appearing as /e/ and sometimes (usually, in fact) as /y/. In Old English, /o/ generally stems from a-mutation of original /u/. A-mutation of /u/ was blocked by a following /i/ or /j/, which later triggered umlaut of the /u/ to /y/. This is why alternations between /o/ and /y/ are common. Umlaut of /o/ to /e/ occurs only when an original /u/ was modified to /o/ by analogy before umlaut took place. For example, dohtor comes from late Proto-Germanic *dohter, from earlier *duhter. The plural in Proto-Germanic was *duhtriz, with /u/ unaffected by a-mutation due to the following /i/. At some point prior to i-mutation, the form *duhtriz was modified to *dohtriz by analogy with the singular form, which then allowed it to be umlauted to a form that resulted in dehter.
A few hundred years after i-umlaut began, another similar change called double umlaut occurred. It was triggered by an /i/ or /j/ in the third or fourth syllable of a word and mutated all previous vowels—but it only worked when the vowel directly preceding the /i/ or /j/ was /u/. This /u/ typically appears as e in Old English or is deleted. Examples are:
- hægtess "witch" < *hagatusjō (cf. Old High German hagazussa)
- ǣmerge "embers" < *āmurjōn < *aimurjōn (cf. Old High German eimurja)
- ǣrende "errand" < *ǣrundjaz (cf. Old Saxon ārundi)
- efstan "to hasten" < archaic œfestan < *ofustan
- ȳmest "upmost" < *uxumistaz (cf. Gothic áuhumists)
As shown by the examples, affected words typically had /u/ in the second syllable, and mostly /a/ in the first syllable. Note also that the /æ/ developed too late to break to ea or to trigger palatalization of a preceding velar.
I-mutation in High German 
I-mutation is visible in Old High German (OHG), c. 800 AD, only on /a/, which was mutated to /e/. By this point, it had already become partly phonologized, since some of the conditioning /i/'s and /j/'s had been deleted or modified. The later history of German, however, shows that /o/ and /u/ were also affected — starting in Middle High German, the remaining conditioning environments disappear and /o/ and /u/ appear as /ø/ and /y/ in the appropriate environments.
This has led to a controversy over when and how i-mutation appeared on these vowels. Some (for example, Herbert Penzl) have suggested that the vowels must have been modified already in OHG, but was not indicated due to the lack of proper symbols, and/or because they were still partly allophonic. Others (e.g. Joseph Voyles) have suggested that the i-mutation of /o/ and /u/ was entirely analogical, and pointed to the lack of i-mutation of these vowels in certain places where it would be expected, in contrast to the consistent mutation of /a/. Perhaps[original research?] the answer is somewhere in between — i-mutation of /o/ and /u/ was indeed phonetic, occurring late in OHG, but later spread analogically to the environments where the conditioning had already disappeared by OHG (this is where failure of i-mutation is most likely). It must also be kept in mind that it is an issue of relative chronology: already early in the history of attested OHG, some umlauting factors are known to have disappeared (such as word-internal j after geminates and clusters), and depending on the age of OHG umlaut, this could explain some cases where expected umlaut is missing.
In modern German, umlaut as a marker of the plural of nouns is a regular feature of the language, and although umlaut itself is no longer a productive force in German, new plurals of this type can be created by analogy. Likewise, umlaut marks the comparative of many adjectives, and other kinds of derived forms. Because of the grammatical importance of such pairs, the German umlaut diacritic was developed, making the phenomenon very visible. The result in German is that the vowels written as <a>, <o>, and <u> become <ä>, <ö>, and <ü>, and the diphthong <au> becomes <äu>: Mann/Männer ("man/men"), lang/länger ("long/longer"), Fuß/Füße ("foot/feet"), Maus/Mäuse ("mouse/mice"), Haus/Häuser ("house/houses"). On the phonetic realisation of these, see German phonology.
I-mutation in Old Saxon 
In Old Saxon, umlaut is much less apparent than in Old Norse. The only vowel that is regularly fronted before an /i/ or /j/ is short /a/. E.g. gast – gesti, slahan – slehis. NB I-umlaut must have had a greater effect than the orthography of OS shows. This is because all the later dialects have regular umlaut of both long and short vowels.
I-mutation in Dutch 
The situation in Old Dutch is similar to the situation found in Old Saxon and Old High German. Late Old Dutch saw a merger of /u/ and /o/, causing their umlauted results to merge as well, giving /ʏ/. The lengthening in open syllables in early Middle Dutch then lengthened and lowered this short /ʏ/ to long /øː/ (spelled eu) in some words. This is parallel to the lowering of /i/ in open syllables to /eː/, as in schip ("ship") – schepen ("ships").
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 Brabant and Holland that were most influential for standard Dutch. Thus for example where modern German has fühlen /ˈfyːlən/ and English has feel /fiːl/ (from Proto-Germanic *fōlijaną), standard Dutch retains a back vowel in the stem in voelen /ˈvulə(n)/. This means that only two of the original Germanic vowels were affected by umlaut at all in western/standard Dutch: /a/, which became /ɛ/, and /u/, which became /ʏ/ (spelled 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 stad "city" which has the irregular umlauted plural steden.
The more eastern dialects of Dutch, including eastern Brabantian and all of Limburgish do have umlaut of long vowels, however. Consequently, these dialects also make grammatical use of umlaut to form plurals and diminutives, much as most other modern Germanic languags do. Compare vulen /vylə(n)/ and menneke "little man" from man.
North Germanic languages 
I-mutation in Old Norse 
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The situation in Old Norse is complicated as there are two forms of i-mutation. Of these two, only one is phonologized.[clarification needed] I-mutation in Old Norse is phonological if:
- In Proto-Norse, the syllable was heavy and followed by vocalic i (*gastiʀ > gestr, but *staði > *stað) or, regardless of syllable weight if followed by consonantal i (*skunja > skyn). The rule is not perfect, as some light syllables were still umlauted: *kuni > kyn, *komiʀ > kømr.
- In Old Norse, the following syllable contains a remaining Proto-Norse i.[why?] For example the root of the dat. sing. of u-stems are i-mutated as the desinence contains a Proto-Norse i, but the dat. sing. of a-stems is not, as their desinence stems from P-N ē.
I-mutation is not phonological if the vowel of a long syllable is i-mutated by a syncopated i. I-mutation does not occur in short syllables.
|a||e (ę)||fagr (fair) / fegrstr (fairest)|
|au||ey||lauss (loose) / leysa (to loosen)|
|á||æ||Áss / Ǽsir|
|jú||ý||ljúga (to lie) / lýgr (lies)|
|o||ø||koma (to come) / kømr (comes)|
|ó||œ||róa (to row) / rœr (rows)|
|u||y||upp (up) / yppa (to lift up)|
|ú||ý||fúll (foul) / fýla (stink, foulness)|
|ǫ||ø (ø̨)||sǫkk (sank) / søkkva (to sink)|
U-mutation in Faroese and Icelandic 
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Another type of mutation occurred in Faroese and Icelandic, where a changed to ø/o in Faroese and ö in Icelandic when preceded by u. Where Icelandic fronted all of its vowels to ö, Faroese did so as well, except in front of nasal consonants where the result was o. In addition, U-umlaut became so strong in Faroese, that even basic forms of words were changed:
- gata → gøta
- saga → søga
See also 
- Cercignani, Fausto (1980). "Early "Umlaut" Phenomena in the Germanic Languages". Language 56 (1): 126–136.
- Cercignani, Fausto (1980). "Alleged Gothic Umlauts". Indogermanische Forschungen 85: 207–213.
- Table adapted from Campbell, Historical Linguistics (2nd edition), 2004, p. 23. See also Malmkjær, The Linguistics Encyclopedia (2nd Edition), 2002, pp. 230-233.
- Ringe 2006, pp. 274, 280
- Duden, Die deutsche Rechtschreibung, 21st edition, p. 133.
- Isert, Jörg. "Fast Food: McDonald's schafft "Big Mäc" und "Fishmäc" ab" [Fast food: McDonald's abolishes "Big Mäc" and "Fishmäc"]. Welt Online (in German). Axel Springer AG. Retrieved 21 April 2012.
- Penzl, H. (1949). "Umlaut and Secondary Umlaut in Old High German". Language 25 (3): 223–240. JSTOR 410084.
- Voyles, Joseph (1992). "On Old High German i-umlaut". In Rauch, Irmengard; Carr, Gerald F.; Kyes, Robert L. On Germanic linguistics: issues and methods.
- Sweet, Henry - An Old Icelandic Primer
- Malmkjær, Kirsten (Ed.) (2002). The linguistics encyclopedia (2nd ed.). London: Routledge, Taylor & Francis Group. ISBN 0-415-22209-5.
- Campbell, Lyle (2004). Historical Linguistics: An Introduction (2nd ed.). Edinburgh University Press.
- Cercignani, Fausto, Early "Umlaut" Phenomena in the Germanic Languages, in «Language», 56/1, 1980, pp. 126–136.
- Cercignani, Fausto, Alleged Gothic Umlauts, in «Indogermanische Forschungen», 85, 1980, pp. 207–213.