These are some of the commonly used initialisms by the Western. Quite fun to use actually! Hehe.
OMG - Oh My God!
GR8 - Great!
TTFN - Ta Ta For Now
BRB - Be right back!
There are also some other example like LOL, LMAO, FGS, XOXO. You can use Mr Google for more info. TTFN!