person in English

The English pronoun system draws three persons and crosses them with number, and the result is a five slot set rather than a six slot one, because the second person has exactly one form for a single addressee and for several. That collapse is the fact worth stating first. A language that keeps distinct singular and plural addressee forms has a contrast English cannot draw, and the language plainly feels the gap, since several regional plurals have been coined to fill it and none belongs to the standard variety. There is no inclusive and exclusive division in the first person plural either, so one form covers both readings and the difference is left to context.

The subject pronoun is obligatory. English is not a language that can drop it: a finite clause without an expressed subject is ungrammatical outside the imperative and a few reduced registers, and the pronoun is what carries the person value in nearly every clause. This is the other side of how little the verb carries. Agreement marks person in exactly one cell of one tense, the third person singular of the present, and the verb be adds two more in its own paradigm. Everywhere else the finite verb is the same string for all three persons, so the ending cannot identify the subject and the pronoun must.

The obligatoriness is recorded as obligatory because the value is settled wherever a pronoun or a finite clause appears, which is nearly everywhere, and the state is explicit because the pronouns are dedicated forms encoding nothing else. What English does not have is any independent marking of person on a noun, on a possessum or on an adposition, all of which some languages carry.