This hashtag in English
In Modern English, you is a singular and plural, second-person pronoun.
You comes from the Proto-Germanic demonstrative base *juz-, *iwwiz from PIE *yu- (second person plural pronoun). Old English had singular, dual, and plural second-person pronouns. The dual form was lost by the twelfth century,:117 and the singular form was lost by the early 1600s. The development is shown in the following table.:117, 120, 121
Early Modern English distinguished between the plural ye and the singular thou. As in many other European languages, English at the time had a T–V distinction, which made the plural forms more respectful and deferential; they were used to address strangers and social superiors. This distinction ultimately led to familiar thou becoming obsolete in modern English, although it persists in some English dialects.
Yourself had developed by the early 14th century, with the plural yourselves attested from 1520.
In Standard Modern English, you has five shapes representing six distinct word forms:
Although there is some dialectal retention of the original plural ye and the original singular thou, most English-speaking groups have lost the original forms. Because of the loss of the original singular-plural distinction, many English dialects belonging to this group have innovated new plural forms of the second person pronoun. Examples of such pronouns sometimes seen and heard include:
You prototypically refers to the addressee along with zero or more other persons, excluding the speaker. You is also used to refer to personified things (e.g., why won't you start? addressed to a car). You is always definite even when it is not specific.
Semantically, you is both singular and plural, though syntactically it is always plural: it always takes a verb form that originally marked the word as plural, (i.e. you are, in common with we are and they are).
You is used to refer to an indeterminate person, as a more common alternative to the very formal indefinite pronoun one.
You always triggers plural verb agreement, even when it is semantically singular.
You can appear as a subject, object, determiner or predicative complement. The reflexive form also appears as an adjunct. You occasionally appears as a modifier in a noun phrase.
Pronouns rarely take dependents, but it is possible for you to have many of the same kind of dependents as other noun phrases.
According to the OED, the following pronunciations are used:
(US) /jɔrˈsɛlvz/, /jʊrˈsɛlvz/
(US) /jɔrˈsɛlf/, /jʊrˈsɛlf/