Germanic modal verbs are preterite-present verbs, which means that their present tense has the form of a vocalic preterite. This is the source of the vowel alternation between singular and plural in German, Dutch and Low Saxon. Because of their preterite origins, modal verbs also lack the suffix (-s in modern English, -t in German, Dutch, Low Saxon and West Frisian) that would normally mark the third person singular form. Afrikaans verbs do not conjugate, and thus Afrikaans non-modal verbs do not have a suffix either: