Affection (linguistics)

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.

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.

Scottish Gaelic
In Gaelic, affection can be seen most clearly in the inflections of nouns and verbs.

Many nouns form their plurals by adding an  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  of the basic form disappears in the derived form:
 * 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  which is the shifted form.

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  itself is silent, but being a "slender vowel" it causes the  to have a slender pronunciation.