Ciao

こんにちは

Oi

Cześć, but in poland we have a lot of ways to say the same word in a difrent way or like a completley difrent word that means the same thing so we can also say, siema (this is more like a slang), hej, dzień dobry, witam, elo (this is also more of a slang word), halo and dobry wieczór

Hola

Salut