Commonly-used slang for
Eblanix, or the language (symbol set, really) used by
elites (and in modern times, more and more magazine layout designers - grr!) using numbers and mathematical symbols to replace letters.
The conversion is thus: 1 = I or l, 3 = E, 4 = A, 5 = S, 7 = T, 8 = B, 9 = G, 0 = O, + = t
The term "hackspeak" in hackspeak would be displayed thus: h4ck5p34k.