Can someone help me understand the different words used for "person" (osoba, czlowiekem, etc.) I'm having a hard time finding the difference and distinguishing which I should use at which time.
Also, is there a neutral pronoun?
Well, this issue turns out to be a lot more complicated than I would expect. Polish and English... just use those words quite differently.
Well, let's focus on Nominative forms ("człowiekiem" is Instrumental). So you have "osoba" (a person), "człowiek" (literally "a human") and their plurals: "osoby" (persons) and "ludzie" (people).
It seems that in English it will mostly sound natural to translate "człowiek" to "person", but "osoba" is used more rarely in Polish. On the other hand, I think that "persons" isn't used that often as Polish "osoby".
OK, so "człowiek" is a human being. A representative of the human race. It can be used generally (The human is the most dangerous species in the world), it can of course refer to one person. Oh yeah, person. It seemed more natural to write that, although it isn't the direct translation... So if I hear "człowiek" and I know that it refers to one person, I think of a man. Actually "a man" can also refer to a human being (not necessarily male), so it is a translation of "człowiek". Especially that "human" isn't used too often as a noun. Why a man? Well, if we knew it's a woman, I think we would specify it and just say "kobieta", not "człowiek". So "Ten człowiek mnie przestraszył" (This human/This man scared me) almost certainly means the same as "Ten mężczyzna mnie przestraszył" (This man/This male human being scared me).
I generally understand "osoba" as a person of unknown gender. "A person that will be the 100th visitor today", "A person that will have the winning lottery ticket", etc. Someone whose identity we don't know. It can be also used in a Political Correctness way - but this is generally mocked in Poland. Another problem is that "osoba" may not in fact refer to a human being. You have The Bible: "Są trzy osoby boskie" (There are three devine persons). Recently in India they recognized dolphins as "non human person" - and regardless of what you think about it, "Indie uznały delfiny za osoby".
In plural, "osoby" will probably be more used. "trzy osoby" are three people ('people' seems more natural than 'persons' here, at least to me) and their gender is either unknown or it doesn't matter. You could say "troje ludzi" (using collective numerals as 'troje' is a difficult thing), but "trzy osoby" does sound more natural to my ear.
Well, that's more or less all that comes to my mind. If something is still unclear, please say it. I think this topic may be really useful to other people.
@Enzfj2 - I think both words have many subtleties. It seems to me, that usually Polish would just specify it more if only that was possible. Anyway, "człowiek nigdy nie wie" sounds possible, but not really common to me...
immery's comment about using "person" here: https://www.duolingo.com/comment/14007328
about neutral pronoun - that depends what you mean. In Polish all words have grammatical gender , and pronoun for neuter nouns is "ono".
But if you need gender neutral pronoun to refer to people- you can use word dziecko=child, and then use "ono", you can use word "osoba=person" and then use "ona", or "człowiek, and then use "on". Using "ono" when talking about people is would be considered rude.