umlauted vowels often serve to distinguish grammatical forms (and thus show similarities to ablaut when viewed synchronically), as can be seen in the English word man. In ancient Germanic, it and some other words had the plural suffix , with the same vowel as the singular. As it contained an , 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 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, and the feminine vixen from fox. 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 and sit. Umlaut could occur in borrowings as well if stressed vowel was coloured by a subsequent front vowel, such as German , "Cologne", from Latin , or , "cheese", from Latin . Parallel umlauts in some modern Germanic languages Umlaut in Germanic verbs Some interesting examples of umlaut involve vowel distinctions in Germanic verbs. Although these are often subsumed under the heading "ablaut" in tables of Germanic irregular verbs, they are a separate phenomenon. Present stem Umlaut in strong verbs A variety of umlaut occurs in the second and third person singular forms of the present tense of some Germanic strong verbs. For example, German ("to catch") has the present tense . The verb ("give") has the present tense , but the shift → 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 triggered a vowel change, but in Proto-Germanic, it affected only . The effect on back vowels did not occur until hundreds of years later, after the Germanic languages had already begun to split up: , with