Formal:
* Siz (pronounced "seez") - This is the formal "you" and is used for someone you don't know well or someone older than you.
* Siz + mısınız? (pronounced "mı-sı-nız?") - This is the formal way to ask "are you?"
Informal:
* Sen (pronounced "sen") - This is the informal "you" and is used for someone you know well or someone younger than you.
* Sen + misin? (pronounced "mi-sin?") - This is the informal way to ask "are you?"
Examples:
* Siz doktor musunuz? (Are you a doctor?) - Formal
* Sen mutlu musun? (Are you happy?) - Informal
Let me know if you want more examples or have other questions about Turkish!