platespeak
n.— «Is one of Britain’s best-loved dialects, the curious language of personalised number plates, heading for oblivion?…Those who cannot afford the best plates have been forced to use a bit of ingenuity to get close to the word or words they really want. Such owners rely on “platespeak,” as it is known in the business, to compose their unique signage—substituting a “5” for an “S,” for example, a “4” for an “A,” and so on.» —“Will UK Law Change Put Car Lingo In Limbo?” by David Wilkins Motorin.co.za (South Africa) Nov. 11, 2008. (source: Double-Tongued Dictionary)