Back slang

Back slang is an English coded language in which the written word is spoken phonemically backwards.
Usage.
Back slang is thought to have originated in Victorian England, being used mainly by market sellers, such as butchers and greengrocers, to have private conversations behind their customers' backs and pass off lower quality goods to less observant customers. The first published reference to it was in 1851, in Henry Mayhew's "London Labour and the London Poor".
Some back slang has entered standard English. For example, the term "yob" was originally back slang for "boy".
Back slang is not only restricted to words spoken phonemically backwards. English frequently makes use of diphthongs, which is an issue for back slang since diphthongs cannot be reversed. The resulting fix slightly alters the traditional back slang. An example is "trousers" and its diphthong "ou", which is replaced with "wo" in the back slang version "reswort".
Back slang is said to be used in prisons by inmates to make it harder for prison wardens to listen into prisoners' conversations and find out what they were talking about.
Back slang has been reported to have been adopted for the sake of privacy on foreign tennis courts by the young English players Laura Robson and Heather Watson.
Other languages.
Other languages have similar coded forms but reversing the order of syllables rather than phonemes. These include: