contraction of you are <I'm glad you're learning how to sound more intelligent!>

a form of the possessive case of you used as an attributive adjective <Your careless disregard for English makes you look stupid.>

one's (used to indicate belonging to oneself or to any person) <Using proper grammar improves your chances of employment.>

(used informally to indicate all members of a group, occupation, etc., or things of a particular type) <You can learn more about these words in your standard dictionary.>