1337 is the language of hackers and newbies across the internet. Also, the words in 1337 are usually short(ie "are" becomes "r") and intentionally spelt wrong(ie "the" becomes "teh", this is most common with e switching places and o's becoming p's)

the mostly complete translation chart(exluding unicode characters, ie ©):
A=4 /-\ @ ^ /\
B=8 ]3 ]8 |3 |8
C=( {
D=) [} |) |} |> > [E=3
F*=# |=
G=6 9 (_>
H=# |-| (-) )-( }{ {-} /-/ \-\
I=1 ! | J**=_| j K=|< |{ L=1 |_ M=/\/\ |\/| \/ N=/\/ |\| \ O=0 () P=|D |* |> Q=0, R=|2 |? |- S=5 T=7 + '' [U=(_) |_| \_\ /_/
V=\/
W=\/\/ |/\| /\
X**=>< }{ X
Y='/ %
Z**=2 z

Common mispellings:
the = teh
that = taht
take = taek
own = pwn
you = joo
dude = jood

common phonetic replacements(always used in true 1337):
f = ph
ck == xx

*there is no 'F' in true 1337, it is replaced by the 'ph' phonetic in true 1337

**acceptable when not replaced by a symbol