If someone simply feels like greeting you, they can. Hello is a greeting that people constantly say to each other.
I say "Hello."
say hello
kitty says hello
when someone says hello you also say HELLO, hahaha der!!
herro is the way someone from china would say hello
You don't need to say hello, its just a polite way of greeting someone.
wave your hand in the air to someone you want to say hello to.
Aloha!
The best resonse back would be "hello".
Hola.
Hello- malo e lelei Goodbye- nofo a (from someone leaving) 'alu a (to someone leaving)
Hello is a traditional greeting, both on and offline. Usually you say it to acknowledge someone else, and let them know they are noticed.