You is a personal pronoun that is singular and plural. Historically, you was only used in the dative case, but it is now used in all cases. It is also a popular substitute for the formal indefinite pronoun one. Using the second person singular form of you automatically triggers the agreement of plural verbs.
The word you has its roots in Middle English and is cognate with the archaic Swedish i and the Old English eow. The two forms are related to the same Proto-Germanic *iwwiz, which is a form of Proto-Indo-European *yus.
The word you is also used to describe hypothetical people. The use of the word you indicates an intimate relationship. It also signifies a superior-to-inferior relationship, although sometimes it is used deliberately to degrade a person. You may also hear people use you to compliment a friend, or use it to warn someone to be careful on Halloween.
You has several forms in American English, including youse and you-uns. However, not all of these forms are equivalent to Standard English. While youse is a more common form, you-all and you-uns are rare in educated speech. Furthermore, the plural you-all is a more informal form, but it is still not a standard form of the word.
You is a contraction of two words, but it doesn’t mean the same thing. This is a contraction, so your spelling might be different as well. You should be careful to avoid using contractions in formal documents, as it may be difficult for spell check to catch them. However, if you are attempting to write a formal document or a letter, be sure to avoid using you-re. However, it is possible to make mistakes using homophones when communicating with native English speakers.
Besides asking yourself what are you doing, you should also ask yourself what are you up to. You can answer this question in many ways by making yourself more aware of your interests. The first way to find out what is on your mind is by asking yourself, “What are you doing?” The second way is to ask, “What are you up to?” It implies what you’re currently doing or planning to do later today. It’s a good way to get to know yourself better.