In the first place, English does not have a formal mode, as many Asian languages do. There are forms of English that are informal, but they all involve non-standard forms, slang or profanity, and are generally considered vulgar. An English speaker will address the queen of England with the same simple, polite sentences that he uses with his own mother.
1. Joan, please remember to delete your files.
2. May I borrow your bike?
3. I would appreciate your help very much.
In (American) English politeness has nothing to do with the speaker's status, eiither as employee and employer, parent and child, or businessman and street beggar. People will use polite forms of address if they are in an environment where it is valued, or if they were raised that way.
In any American office you may hear:
1. Joan, you idiot! If I have to tell you again to dump that trash, your butt is going to be out on the street!
2. You really look hot on that new bike of yours. You mind if I take it for a spin?
You get the idea.
- For Teachers