Koreans usually starts a conversation with a Hi,so saying hello is very important in their tradition.There are different ways to say hello in their language.They use different variations in their conversation depending on the people involved in it.The major ones are casual, polite, and formal.
When they are speak with friends,family or ones who are younger to or junior ,they tend to be casual or more closer and comfortable.They say Annyeong – “Hi”
When they are speaking to people whom they know but not friends or close acquaintance,they keep a safe distance and be more guarded.Here they use (Annyeong Haseyo) – “Hello”.This is the most common way they greet people in Korea.
When they are talking to complete strangers or in an official conversation with their seniors they maintain a formal tone .They say annyeong hasimnikka - Hello
They use this Yeoboseyo – “Hello” while using the telephone.This way they use to get someones attention too or when they are not sure whom they are talking to on the telephone..