I have a working knowledge of Polish, and can understand it, especially in written form. But any intricacies of the language are foreign to me.

I don’t know how genuine problem this is but the ethnonym “Ukrainian” has entered circulation rather recently, and it comes from Polish. The first to speak of Ukrainian nation (украинская народность) was the historian Nikolai Kostomarov in an essay titled “Two Russian nationalities.” Where he said there are two branches of Russians, Greater Russians and Ukrainians. This however cannot be considered the first use of the ethnonym Украинец.

The latter was adopted by some circles by the end of the nineteenth century but remained widespread among political activists and intellectuals only. By the outbreak of the First World War and especially towards its end, this identification got more currency. (See my posts here and here and here). I recall Oles’ Buzyna saying that the ethnonym “Ukrainian” was first officially used in the Austro-Hungarian military in 1916, on the orders of Emperor Karl I.

Otherwise it took root in 1920s during Soviet Korenizatsiya…