actually, Crystal Clair was asking about "yo" at the beginning of a sentence. In which case, I think it pretty much works exactly like it does in English (ex. "Yo, genki da na?" would be "Yo! How ya doin'?").
To add onto what buster_wolf said about the verb endings, it's also worth noting that "i" is not always to indicate politeness (that's only if you add "masu" or similar things to it). If you add "tai" to the end of an "i" word, you're basically saying "I want to (verb)". Likewise, if you add "ba" at the end of an "e", you're pretty much saying "if", thus you can follow with what would result if said verb were carried out. You can also end verbs with "o".... if you're familiar with the "mashou" ending, that's pretty much the same except more casual (ex. "ikimashou" and "ikou", which are based off of "iku", making it "let's go", I think).
I also noticed that you could add "nasai" to the end of an "i"... I don't quite know what it means, but from the context I've seen it in, it's some kind of polite way of commanding (like the "e" ending that buster_wolf brought up). I'd like some confirmation if anyone knows.
mistywishmaker said:
I think ある is only meant for inanimate objects. When you're speaking of a person, or other living things, you use いる.
