To me the hardest thing about learning English was that you pronounce the words differently than you write them. Now a lot of native English speakers asked what I am talking about, but listen, slavic languages pronounce letters differently, and we DON'T have silent letters.
For example you have the word "queue" which you pronounce simply "Q", but a Polish person will read ALL the letters in that word, so we'd say "Q-weh-weh". Because we never heard about silent letters in a word before.
English has a lot of nuances like that.
Don't let me start on how many times I confused W with V, because we don't have V in our alphabet either. Where I come from W/V are pronounced the same.
I simply couldn't see the difference between "never / newer", "lover / lower" etc
But right back at you you, because you guys have no idea what's the difference between ś/si/sz is or why we have 3 different Z's in our alphabet (Z, Ź, Ż) lol
Second hardest thing is pronounciation itself. Polish has a lot of words that have a variety of "sh" sounds in them, and some of them don't even exist in English. Polish is a very rough sounding language. Our tongue positioning while speaking is different than in English, so I feel like my tongue will knot while speaking English XD
It's like trying to talk to aliens or eldritch gods XD
Then there's accent. You guys pur emphasis on the syllabes in different places than Polish, same goes to sentences. And when done wrong, in every language, it's hard to recognize a word correctly.