Finnish has different forms of noun-like words when referring to more than one, i.e. plural forms, as opposite to the basic form, singular. Similarly, for finite forms of verbs, there are separate singular and plural forms according to whether the subject refers to one or more. This is part of the inflection of verbs in person forms.
Predecessors of Finnish also had dual, used to refer to exactly two. All that is left of this—apart from some suffixes that are believed to have originally had a dual meaning—is that there are some dual pronouns. They refer either to exactly two things or to one of exactly two. For example, in addition to the normal interrogative pronouns kuka (who) and mikä (which, what), there is the dual pronoun kumpi (who/which of two).