Concerning alternate nouns for "Woman", how does one tell plurality?

I've been somewhat involved with the Feminist movement for a few years now, and something I see now and then is an alteration on the accepted spelling of the words "Woman" and "Women" (examples include "Womyn" and "Womon"). What I have trouble seeing is any cohesive pattern to these changes that can tell me whether the topic of conservation is one woman or multiple women.

I understand that these words are technically slang, but I still get the feeling that there's a pattern or something that I'm missing. I have no intention of using these words myself, but considering they do appear in some pieces of Feminist literature, having this issue cleared up would be a great help.