When you are addressing agroup of people as you, how do you differentiate between speaking to just oneperson? Unlike many of its linguistic neighbors, English technically only hasone second person pronoun. Languages like German and French have two words for you - one for speaking to one person andone for multiple people, and the second term in many cases doubles as a moreformal manner of speaking to one person - tu versus vous in French, forexample.
In earlier times, English did have a second person plural - ye- while the original first person singular, the ancestor of you, was thou, which is still used insome areas. As the influence of French grammatical structures grew on ourdeveloping language, ye also came to be a more formal, polite mode of addresswhile thou was the familiar form.
While ye and thou are stillused in rare circumstances in some areas, they had largely disappeared frommost mainstream English speech by the end of the 18th century. Theexact reasons why continues to be a matter of study and debate however it isquite likely that the reason was social. Separate you's for addressing equals versus addressing superiors hints at anunderlying social hierarchy. In many situations addressing someone as thou -that is, as a social equal - could be perceived as an insult. Perhapsincreasing trends of egalitarianism in English society over the centuries wereresponsible for this change, or perhaps the growing influence of Americanculture and the importance it placed on social mobility played a role.
Regardless of the reason,none of the current definitions of "proper English" require these terms. ModernEnglish according to those who attempt to rule it does not differentiatebetween singular and plural or formal and informal in the second person. Thisis unfortunate, as a second person plural is a very practical bit of language.Luckily, language is good at adapting and slipping around the confines peopletry to put it in. In spite of the official ban on the pronoun, the languageitself has evolved in many areas to fill the need. For example:
Y'all is a prominentfeature of Southern American and African American vernacular English as well asa few other dialects, encompassing huge swaths of America's population. While theword is still considered unacceptable in formal language, the term is nowcommon in an increasingly wide variety of demographics in virtually every areaof the country.
Yinz is a wordusually associated with the city of Pittsburgh,although its usage extends into the mountains of western Pennsylvania. According to Pittsburgh Speech & Society, the term was brought to the region by Scots-Irish settlers inthe 18th century, who used the term you'uns (you ones) which evolvedinto yinz. Usage of yinz is a good example of the connection between a mode ofaddress and social hierarchies - the word yinzer is a somewhat derogatory termfor working class natives of the city.
While yinz shows no signs ofspreading far beyond Pittsburgh,y'all's usage has become increasingly mainstream. What does this say about thefuture of the English language? It certainly shows how quickly a language canevolve in response to cultural change and the need to fill a gap in how peoplecommunicate. It's possible that by the end of the 20th century, youand y'all will both be considered grammatically correct.