Translation:How are you?
I believe it has to do with formality... Like you might say "?מה נשמע" to a friend, whereas you might would use "?מה שלומך" with someone you just met, or for that one cashier you repeatedly bump at the grocery store... That's just my current assumption though. I could be totally and completely wrong, haha. . Any native speakers out there able to shed some better light on the usages?
The phrase מה נשמע literally means "What will we hear" and is used to ask "What's new" or something similar. I'm not an expert, but it sounds like something that would be used in a more familiar setting. This is how I learned it from another program. Anyone else have insight into this? שלום
מה נשמע?, מה קורה? are informal way of greeting ,you probably will not say to some you don't know מה נשמע, מה קורה you would say then just SHALOM or SHALOM LECHA/LACH and only then you can say MA NISHMA and MA KORE but MA KORE is more slang and used between youngers mostly. Now HOW ARE YOU, which is not formal in hebrew, will be literally "EICH ATA (masculine) and EICH AT (feminine). it is not so popular as MA NISHMA or MA KORE but is quite common as well. Formally, you will greet with SHALOM, after saying shalom and got responded back with SHALOM you can add MA NISHMA, that will kind of brake the ice of formality after each one of you understood you are OK one with each other.
They are not very different. Different people might give you different nuances. Here is my take: מה נשמע is my (and many others') default - I'd say it to anyone, from colleagues at work, through small shop owners I visit often enough to know one another, to my wife when we meet at home after work. I expect some bland answer, unless there's something really special they want to share.
Now מה קורה is the same, except it's slang of a somewhat younger generation. I though I tend not to use it, but now I'm not 100% sure...
Lastly, מה שלומך rings to me like having a bit more concern - maybe you have been unwell, and I want to know whether you're better (or worse) now.