Grammatical person shows distinction between references to participants of an action. It's closely related to set of personal pronouns and affects verbs. See Wikipedia for more information.

In Nûrlâm verb's category of person is expressed via clitic personal pronouns, and standalone pronouns are often omitted. So, if standalone pronoun is used then verb doesn't have marker of person. There are three persons similarly to many European languages. However according to popular belief that Sauron forbade using 1st person singular (“I”), only 3rd person pronouns and verbs has separate form of singular number. This part of the language was changed several times during creation of Nûrlâm dialect and in Black Speech hypothetical history.