Difference in register between hello, hi, hey and haya I came across this: http://vk.com/wall-33489538_468109 I wonder which of these greetings are more formal and which are more informal. Longman Dictionary of Contemporary English says: hello used when you meet someone, or when you start a telephone conversation. In everyday English, most people usually say hi because it sounds more friendly. You use hello especially when talking to people you do not know well, or to older people hi used as a friendly greeting when you meet someone start a telephone conversation, or at the beginning of an email hey (especially American English informal) used as a friendly greeting when you see someone you know well and you want to start talking to them hiya (informal) used as a very informal greeting when speaking to someone you know well Am I right that 'hi' is a bit formal, 'hello' is less formal, 'hey' is even more informal, and 'hiya' is the most informal?