OK, first thing's first. When you play Runescape, someone may say "ty" or "np" and you wonder what that means. Well, here is a key for every thing that people use in Runescape that is shortened or changed in some way.
U = you
R= are
Y= why
C= see/sea
lol= laugh out loud
rofl= rolling on the floor laughing
ya= yeah or regular meaning
Ty= Thank you
Np= No problem
Yw= Your welcome
Welx= Your Welcome
Wut/Wat= What
Brb= Be right back
Bbl= Be back later
Xp= Experience
gp= Gold pounds, (at least I think) the currency in Runescape
K used after a number= 1,000, used particularly with money and experience, but
you can usually tell which (ex: 3k= 3,000gp or 3,000xp)
Mil used after a number= 1,000,000gp (ex: 3mil= 3,000,000gp)
Gtg/g2g= got to go
4= for or regular meaning
2= too/to or regular meaning
Sry= sorry
Ppl= People
K/Kk= OK
PK/pk= Player killer/Player kill
Kno= Know
Lv= Level
Rs= Runescape
Mith= Mithril
Addy=Adamant/Adamantite
HP= Hit Points
Scimmy= Scimitar
2h= two handed
Essence= Rune Essence
Lobby= Lobsters
Fally= Falador
Lumby= Lumbridge
Sn= screen name
Full used before a kind of armor (ex: full rune)= Full helm, Platebody,
platelegs, and kiteshield of the same type
Pl8=plate
Sk8=skate
Pass=password (for some reason password gets censored, I guess so you can't ask
others for their password)
Telegrab= Telekinetic Grab (a magic spell available at lv 33, uses a law rune
and an air rune)
Lesser= A Lesser Demon (lv 82)
Greater= A Greater Demon (lv 92)
Zammy= Zamorak
Those are all that I know of . One thing to know is that if you make a typo (which is common) put an asterisk (*) and correct the error. Or you could simply say ,"I mean...". Also, in terms of swears; you are not allowed to swear. If you say an offensive word or a swear, then it is automatically censored like this: ****. I don't use them, and you shouldn't either, because if someone is offended by it, they can report you for offensive language. Reports may not do much, but if you get enough, then you can get suspended, or even possibly banned. I can't make you not swear, but I can warn you; if you do, do it rarely.