When we talk about people, we often use the plural form of you. Historically, you was only used in the dative case but has now been used in all cases and numbers. The second-person plural form is also sometimes used. You can also be pluralized by using the possessive form. Here are some examples.
In American English, the second-person singular or plural is used to refer to the person or people involved in a conversation. It is an informal form that conveys the notion that the person is aware of the context. It is also sometimes used in combination with the subject and is sometimes repeated for emphasis. The plural form is also used when addressing a group of people.