Formal:
* Tumi kôthāy ācho? (তুমি কোথায় আছো?) - This is the most common and polite way to ask someone "Where are you?"
* Apni kôthāy āchen? (আপনি কোথায় আছেন?) - This is even more formal and is used when addressing someone older or in a position of authority.
Informal:
* Tumi kôthāy? (তুমি কোথায়?) - This is a shorter and more casual way to ask.
* Ki kôro? (কি করো?) - This literally means "What are you doing?" but can be used to ask "Where are you?" in a more informal setting.
Other variations:
* Kôthāy ache? (কোথায় আছে?) - This is a more direct way to ask "Where is it?" and can be used for both people and things.
* Tumi kôthāy jaচ্ছো? (তুমি কোথায় যাচ্ছো?) - This means "Where are you going?"
* Kôthāy chilo? (কোথায় ছিলো?) - This means "Where were you?"
The best way to choose the right phrase depends on the context and the person you are speaking to.