"hi" in polish: "Cześć" you read it like "cheshch" :)
and "good day" (bec we dont have good morning, afternoon etc) ==> "dzień dobry"

hi, in muslims say simply aslam-o-alaikum

Oh-ok. Do you know Urdu by chance?

Hungarian: szia
Romanian: salut

arabic : al salam alikom :)

he most popular word to say hi is labas. It can be said informally to anyone.

Another popular informal way of saying hello is sveikas, sveika, sveiki and sveikos. These words are dependant on gender and number. Sveikas is said to one male person, whereas sveika is a greeting to one female. Sveiki is said to more than one male, and sveikos is used to greet more than one female. If the group is mixed (males and females), you have to use sveiki.

When addressing people you don't know, older people or persons of authority (teachers, etc), you must use one of the following phrases depending on daytime:

Labas rytas or labą rytą in the morning. Laba diena or labą dieną in the afternoon. Labas vakaras or labą vakarą in the evening.

issamus paiskinimas :D nezinojau tiek..:)

In arbic language Al-salam alaykoum

Does that vary by country?

Thanks.:) Do you know what Urdu's is by chance?

Ya!!!
It's d same as in Arabic..
"Al salaam Aleikum {pronounced "As'sa-laa'm A-ley-koom}

Thanks.:)