To zdanie jest całkiem złe! Nie jestem ptakiem, ale umiem latać, bo jestem nietoperzem!
Yes to both :-) Umieć means to know how to, in the sense of having a skill, being able or capable to do something. There are no specific word in English meaning the same as umieć, so it would be translated using different verbs in different contexts.
- "Umiem liczyć"-> I know how to count.
- "Umiem latać" -> I can fly.
- "Umiem pływać" -> I can swim.
For some reason, "You are not a bird, and you are not able to fly" is flagged incorrect for me.
Can both możesz and umiesz be used here for you cannot fly, with możesz implying not being able to, and umiesz implying not knowing how to. In fact “Google translate” will translate “you cannot fly” as nie możesz latać.
Well, Google Translate is hardly a reliable source, but well, it's right here. Although I'd rather say that "not being able to" is still closer to "umiesz", and "nie możesz" is more like "you are not allowed to".