The French phrase for "How are you?" is an important one to learn for conversing with French speakers. While different versions of the phrase will be best suited for different situations, learning these phrases is easy enough. Once you have mastered the phrases, practice them to learn when to use each one.
Asking "How Are You?" in French
The formal version of "how are you?" is used as a sign of respect, particularly when speaking with elders, or as a sign of distance because you don't know the person with whom you are talking.
Pronounced, co-moh-tall-ay-voo (the single letter 'o' is pronounced long, as in the 'o' in show) This phrase is a direct translation of "how are you?" and is formed with the formal 'you' pronoun 'vous.' This is also the form you would use when asking a group of people how they are doing, even if they are all close friends.
Pronounced coh-moh-vah-too, (the single letter 'o' is pronounced long as in the 'o' in show), this is the same question as the previous one, but with the pronoun 'tu,' which is the informal version of 'vous.'
'Vous' or 'tu'?
Deciding when to use these two forms can be tricky for learners. When in doubt, use 'vous'. If you've gauged incorrectly, the person in question will immediately request that you address him with 'tu.'
Traditionally, it is the older person who decides if he or she wants to be addressed with 'vous' or not. Once you know someone well enough or have completed enough education to be considered a peer, the individual will say: "Tutoie-moi, s'il te plaît" (Too-twah-mwah see-tuh-play), thereby giving you permission to use tu.
While young people have the tendency to use 'vous' less frequently than older people, it is impolite to do so when speaking with elders unless you have been given permission to do so by the person in question.
Asking Friends How They Are
In informal situations, you might take an additional step toward informality beyond just using 'tu' instead of 'vous.' Among friends and family, and especially among young people who are friends, it is common to ask "Comment ça va?" (Coh-moh-sah-vah; 'o' is long) or simply "Ça va?" (Sah vah) These are more translations of "How's it going?" as opposed to "how are you?" Never use these phrases with strangers, unless the situation is extremely informal. Again, when in doubt, err on the side of caution. The person with whom you're speaking will let you know a more informal title is preferred.
Practicing Formal and Informal Speaking
If your native language is English, volleying back and forth between the formal and informal dialogue of French can be confusing at first, but a little practice goes a long way. Even though there's no formal version of 'you' in English, tones change when speaking in more formal situations. Think of the 'vous' form in this light to help you keep it straight in context.