I'm still very much a beginner at Polish, although I do know and recognize some things. One of the hardest things about Polish is the pronunciation. I actually don't think it's all that difficult, but there are some groups of letters that take practice. Polish abounds with "sh" "ch" "zh" sounds, which are fine on their own, but it's not uncommon for these sounds to be combined, making some words a bit of a challenge. There are also two nasal vowels: ą (this one I have down pretty well) and ę (this one I need to work on more). I also keep wanting to pronounce y like "ee," but I think it's supposed to be more like "ih."