Co tam u ciebie vs. Jak sie masz?
I just started talking to Polish people, and some of them use "Co tam u ciebie" while others say "Jak sie masz". When would I use these?
You can use both in the same context, but "Co tam u ciebie?" is more like "What's going on?" and "Jak się masz?" is more like "how are you?"
I don't know if others will agree with me, but I personally don't ever use Jak się masz?. I know it's a neat translation for how are you? but to me it seems just a bit outdated. I might sometimes use Jak się miewasz? jokingly.
Generally, I feel like in Polish you don't ask someone how they are unless you really mean it and if you do ask, instead of a I'am fine thanks you will get an honest answer. So for example if I know that someone hasn't been well I might ask them Jak się czujesz?.
On the other hand, if it's a conversation starter, I would say Co słychać? / Co u ciebie? / Co u ciebie słychać? / Co tam u ciebie? / Co tam u ciebie słychać? or Co porabiasz? if I know the person and if I don't I'd just say Miło cię poznać.