Dual (abbreviated DU) is a grammatical number that some languages use in addition to singular and plural. When a noun or pronoun appears in dual form, it is interpreted as referring to precisely two of the entities (objects or persons) identified by the noun or pronoun acting as a single unit or in unison. Verbs can also have dual agreement forms in these languages. The dual number existed in Proto-Indo-European, persisted in many of its descendants, such as Ancient Greek and Sanskrit, which have dual forms across nouns, verbs, and adjectives, Gothic, which used dual forms in pronouns and verbs...