Ni Hao!

If you ever travel to the "West" you will find that we have many different ways to say, "Hello!"

In the U. K. someone might say "Cheerio!"
In Australia "G'Day, Mate!"

In the U. S., we have many ways to say, "Hello," often depending on where you are in the U. S.

In the north and Midwest people usually say, "Hi!" or "How are you?"
In the Southwest they say "Howdy!"
In the South "Hey!"

Slang
There are also many "slang" words for hello, like

"Wazzup?"
"Yo"
"How YOU doin'?"
"What's Happ' nin?" (no 'g')

So don't be surprised if you hear someone say "hello" to you in a way you did not expect.