English traditionally distinguishes three grammatical persons:
The personal pronouns "I" and "we" are said to be in the first person. The speaker uses this in the singular to refer to himself; in the plural, to speak of a group of people of which he is a member.
The personal pronoun "you" is the second person pronoun. It refers to the person spoken to. You is used in both the singular and plural; the old second person singular pronoun, thou, is archaic in modern English.
All other pronouns and all nouns are in the third person. This person is traditionally defined to be what is spoken of or anything that is not first or second person. People who are neither the speaker nor the person spoken to, and any inanimate objects, are referred to in the third person.
In Indo-European languages, first, second, and third person pronouns are all marked for singular and plural forms, and perhaps dual forms as well. Some languages, especially in Western Europe, distinguish degress of formality and informality. Common ways of doing this include using the second person plural pronoun as a singular in formal situations (as in French); or using an old third person noun, with its third person verb forms, as a second person form of address (as in Castilian Spanish). European languages that exhibit these features of contrasting formality and informality have a T-V distinction, named for tu and vous, the informal and formal second person pronouns. (See also thou).
Other languages use different classifying schemes, especially in the plural pronouns. One frequently found difference not present in most Indo-European languages is a contrast between inclusive "we", a first person plural pronoun which includes the person addressed in the group of "us," and exclusive "we", which excludes the person addressed. These languages would use different pronouns, verb forms, or both to translate these two sentences:
Other languages have much more elaborate systems of formality that go well beyond the T-V distinction, and use many different pronouns and verb forms that express the speaker's relationship with the people she addresses. The Japanese language has one well known such system; many Malayo-Polynesian languages have them as well.