Green’s Dictionary of Slang

(UK und.) backslang, lit. an inversion of ‘back-talk’.

1923

(con. late 19C) Northern Whig 12 Sept. 8/6: ‘Ka-cab-Ka-lat’ [...] was the favourite ‘flash patter’ of the costermonger class [...] ‘Kacab-Kalat’ is really ‘back-talk’. One shop-boy would ask another, ‘Where’s the retsam?’ and the reply [...] ‘Texan Road,’ or ‘Enog to rennid.’ This interchange simply meant ‘Where’s the master?’ with the answer ‘Next door’ or ‘Gone to dinner’.