Germanic umlaut

The Germanic umlaut (sometimes called i-umlaut or i-mutation) is a type of linguistic umlaut in which a back vowel changes to the associated front vowel (fronting) or a front vowel becomes closer to /i/ (raising) when the following syllable contains /i/, /iː/, or /j/.

It took place separately in various Germanic languages starting around 450 or 500 CE and affected all of the early languages except Gothic. An example of the resulting vowel alternation is the English plural foot ~ feet (from Proto-Germanic *fōts, pl. *fōtiz). Germanic umlaut, as covered in this article, does not include other historical vowel phenomena that operated in the history of the Germanic languages such as Germanic a-mutation and the various language-specific processes of u-mutation, nor the earlier Indo-European ablaut (vowel gradation), which is observable in the conjugation of Germanic strong verbs such as sing/sang/sung.

While Germanic umlaut has had important consequences for all modern Germanic languages, its effects are particularly apparent in German, because vowels resulting from umlaut are generally spelled with a specific set of letters: ⟨ä⟩, ⟨ö⟩, and ⟨ü⟩, usually pronounced /ɛ/ (formerly /æ/), /ø/, and /y/. Umlaut is a form of assimilation or vowel harmony, the process by which one speech sound is altered to make it more like another adjacent sound. If a word has two vowels with 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 together; 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 and Old Norse and apparently later in Old High German, and some other old Germanic languages. The precise developments varied from one language to another, but the general trend was this:

The fronted variant caused by umlaut was originally allophonic (a variant sound automatically predictable from context), but it later became phonemic when the context was lost but the variant sound remained. The following examples show how, when final -i was lost, the variant sound -ȳ- became a new phoneme in Old English.

The following table surveys how Proto-Germanic vowels which later underwent i-umlaut generally appear in modern languages—though there are many exceptions to these patterns owing to other sound changes and chance variations. The table gives two West Germanic examples (English and German) and two North Germanic examples (Swedish, from the east, and Icelandic, from the west). Spellings are marked by pointy brackets (⟨...⟩) and pronunciation, given in the international phonetic alphabet, in slashes (/.../).

Whereas modern English does not have any special letters for vowels produced by i-umlaut, in German the letters ⟨ä⟩, ⟨ö⟩, and ⟨ü⟩ almost always represent umlauted vowels (see further below). Likewise, Swedish ⟨ä⟩, ⟨ö⟩, and ⟨y⟩ and Icelandic ⟨æ⟩, ⟨y⟩, ⟨ý⟩, and ⟨ey⟩ are almost always used for vowels produced by i-umlaut. However, German ⟨eu⟩ represents vowels from multiple sources, which is also the case for ⟨e⟩ in Swedish and Icelandic.

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⟩. This is a neat solution when pairs of words with and without umlaut mutation are compared, as in umlauted plurals like Mutter – Mütter ("mother" – "mothers").