Substituting letters with numbers - what's it called?

I see numbers in place of letters to form words (example: a number plate that reads “CYA L8R” to mean “see you later”)

Is there a word to describe either the result (i.e, “CYA L8R”), or the act?

l33t sp33k?

Leetspeak, textspeak/txtspk, or The Decline of Western Civilisation. Free choice, one of three. :wink:

Thanks for the quick answer!

(I think Sign of the Decline of Western Civilisation is good) :wink:

I don’t have an answer to the OP, but I do think the answers provided don’t stand up.

This manner of alternate spelling is, at the very least, as old as personalized license plates- thus, it significantly predates the l33t sp33k or textspeak phenomena.

Bumper Stumpers?

The Arabic Chat Alphabet (an artifact of the ASCII internet age) uses these a lot for Arabic letters that don’t have equivalent Roman letters:

ء=2
ع=3
ط=6
ح=7
ص=9

using the same shape-similarity principle as in 1337.

Isn’t this essentially a rebus?

78, Derleth

Online etymology dates rebus to 1605.

Of course. Upon founding the Journal of Lucky Beer Bottle Cap Studies, we specifically included numericals as an independent and primary branch of our pursuit. Several of our scholars have gone on to specialize only in numericals, and might correct you for referring to what they do in such a general way, but they would never deny their debt to rebus studies as their entry to Rabelaisian representation.