In Celtic linguistics, affection (or more precisely "i-affection") is the fronting of vowels in the main syllable of a word caused by an original front vowel in a suffix which may or may not still be present in the modern language. The words Celt and Celtic can have a variety of meanings. ...

Affection is thus an example of i-mutation, and may be compared to Germanic umlaut. More rarely, the term "affection" (like "umlaut") may be heard applied to other languages, and is then a synonym for i-mutation generally. I-mutation is what umlaut is called when it applies to English. ... In linguistics, the process of umlaut (from German um- around + Laut sound) is a process whereby a vowel is pronounced more like a vowel or semivowel in a following syllable. ...

Scottish Gaelic

Further information: Scottish Gaelic grammar

In Gaelic, affection can be seen most clearly in the inflections of nouns and verbs. To meet Wikipedias quality standards, this article or section may require cleanup. ... // Scottish Gaelic (Gàidhlig) is a member of the Goidelic branch of Celtic languages. ...

Many nouns form their plurals by adding an <i> after the vowel of their main syllable:

cat ('cat') → cait ('cats')

A slightly irregular example is:

cù ('dog') → coin ('dogs')

Thus the singular contains the original vowel, while the plural has a shifted form caused by the /i:/ vowel of the original suffix, which has long since disappeared.

In verbs, it is the citation form which contains the shifted vowel, giving the illusion that the <i> of the basic form disappears in the derived form: In linguistics, citation form is the way a word is prononunced when it is spoken carefully and in isolation, such as when reading a list of words. ...

cuir ('put') → cur ('putting')

This may be compared to the Germanic phenomenon of Rückumlaut. In fact, of course, notwithstanding the conventions of dictionary citation, it is the form with the <i> which is the shifted form. In linguistics, the process of umlaut (from German um- around + Laut sound) is a process whereby a vowel is pronounced more like a vowel or semivowel in a following syllable. ...

As Gaelic spelling is very conservative, affection is neatly displayed in the written form. In spoken Gaelic the effect is often no longer heard as fronting, but may have other results. For example, in cait the <i> itself is silent, but being a "slender vowel" it causes the <t> to have a slender pronunciation.

See also

• I-mutation