The inflectional category of number is shared by nouns, adjectives, pronouns and verbs. Number answers the question "how many?" For nouns and pronouns, it tells us how many objects are being referred to. The number of an adjective echoes the number of the noun it is modifying, and the number of a verb echoes the number of the subject, whether that subject is explicitly stated or implied.

Gothic, the earliest attested Germanic language, had not only the two numbers we are familiar with (singular and plural), but also a third. The dual tells us that there are two of the object in question. Gothic had dual first- and second-person pronouns and dual verb endings to match. Old English, fortunately, retains distinctive dual forms only in the pronoun paradigm: it uses plural verbs with these dual pronouns. Since modern readers find the dual pronouns charming, they also find them easy to learn.