Cośmy zrobili?

Question … can anyone help? Is ‘‘cośmy’’ a valid word? I’ve checked a few dictionaries and I can’t find it. Thanks

Yes, it’s a valid word incorporating the first person plural suffix “-śmy”. This use is a bit old-fashioned and colloquial.

You can do the same with “-ście” (second person plural). There are also independent particles such as “żeśmy” and “żeście” which mean pretty much the same thing, and they are also very colloquial, and slowly going out of use.

In this specific sentence, they’re used to emphasize the word “co” (as in: “WHAT have we done?” or even “What the hell have we done?”).

I think it’s good to know that those exist so that you can decipher the meaning when you see them, but you definitely don’t need to learn to use them yourself.

Here’s a pretty good thread on the subject:ś_m_śmy_ście/goqpbur/?utm_source=reddit&utm_medium=web2x&context=3