Copulatives
A copulative is a word which does the work of a predicative, and which is formed from some other part of speech by modification of a prefix or concord, or by means of some formative addition.
Complete predicates and sentences may be formed with substantives, qualificatives, or adverbs without employing any verbs, according to definite rules. These copulatives generally take the place of the verb "to be" in English. In Sesotho, there are also conjugations of the copulative using verbs (-ba, -le, and -na, as well as their inflected forms) giving meanings of "to become" and "to have."
Read more about this topic: Sotho Parts Of Speech