Standard expectation is at least two solid paragraphs. The first should be 4 to 5 sentences reacting to what's going on. This is where you'll acknowledge any statements made to you, remark about an action, or just make observations. These can be done with dialog, inner monologue, or just narrative description. Think like we're all writing a fan-fic, taking turns from our characters' perspective.

The second paragraph should contribute to the posting. Your character will usually say or do something at this time that people can react to. Obviously, the amount of paragraphs and what you are actually saying/doing in them varies based on what is going on in the RP and what the other players may have posted. If we're in the middle of a fight or nobody acknowledged you while we stand around and BS, your posts may be shorter than if you are taking the lead on an investigation or just doing something alone, left to your thoughts.

The golden rule is never control another player's character. This includes conversation and action. You can suggest they do something, either with dialog or descriptive narrative, and continue writing. However, you should try to phrase the rest of your post to be a little open-ended and not assume they agree when they may do something else. Because of this, most players generally wrap up their posts with the said suggestion or engaging dialog with another player. Unlike table top, we don't meet at scheduled times. Instead, players are encouraged to check at least once a day and make a post.

I hope that cleared it enough to help you get your first post. If you have any other questions, feel free to ask here or text me. You can also check this link, which may have some other useful information for you.

[url=http://www.roleplayerguild.com/topics/4958/posts/ooc]

EDIT: Hahahah xD other golden rule, never do one liners! Even if it's all you can think of, you B.S. like I said, here on advanced their is the expectation of at least two thought out paragraphs. My bad for not clearing that up, I have a lot to teach you about my neck of the woods lol

EDIT2: It is player preference. If it is still clear what is being said, you can write out the accent, but some accents can get choppy and difficult to read so most find it safer to just write in English and the accent is assumed.