This is the most common greeting, and it’s pronounced “nǐ hǎo” (knee-ha-oh). If you want to be more polite, like if you need to show respect to elders, for example, you should change it to ‘您好’ (nín hǎo).
“Labas!” is the most common greeting, and is what they say in the shops and so on. It’s also how you’d address your friends and family. Pronounced “La-buzz”, or something like that, it’s a bit hard for me to describe. One online source suggests comparing it to Spanish pronunciation, which works – say it as if it’s a Spanish word. If you don’t speak any Spanish, well… tough. Just do your best, I s’pose.
Obviously it’s not that straightforward, and you’d be shot or at least frowned at if you tried to greet a superior at work, or an older person, with a cheery “Labas!”. I think you’d be better to go with “Svieki!” in that case, but don’t ask me how to pronounce that. Then, of course, there are the variations depending on the gender of the person you’re greeting, and whether you’re talking to one person or several, and whether it’s morning or night…
I’m sticking with “Labas!”, and avoiding old people and men in suits.
Pronounced something like “Grew-EAT-sy!” (I think. Swiss German dialects are hard!), this is what people in many (but not all) German-speaking parts of Switzerland say as an all-day greeting instead of “good morning”, “good afternoon”, “good evening” and so on. It’s quite polite and formal, and comes from the German “ich grüsse sie” meaning “I greet you”.
If you’re talking to your friends and have no need for formalities, just say “Hoi!”. It means “Hey” or “Hi” and seems an awful lot easier to pronounce…!
“Hejsan!” is probably the closest word that the Swedes have to “Hello!”, and is pronounced “HEY-san!”. There are other common variations, too. The abbreviated form, “Hej!”, is more like “Hey!” or “Hi!”. “God dag!” is more formal, meaning “Good day!”. Alternatively, you might hear “Hallå!”, which is generally used when answering the phone.
There’s also “Tja!” (pronounced “Sha!”), which is apparently “very informal”, but I have no idea what that actually means. The Swedish equivalent of “Bout ye?”, perhaps?
“Labdien!” means “Good day!” and is pronounced “Lab-DEE-an!”. It all gets a bit more complicated if you want to be less formal and say a simple “hi!”. The word is “Sveiki!”… if you’re saying hello to a group of people. If it’s just one friend, however, you’ll have to alter it slightly, to “Sveiks!”… oh, but wait a second…. that’s unless the one friend is a female rather than a male, in which case you’ll have to say “Sveika!”.