Shelta, Gammon or the Cant is (was) a form of slang used by gypsies in the British Isles. Among many other curious techniques to obscure the overt meaning of words, Shelta uses the same process of syllable inversion as Lunfardo: thus, mac, the Irish for son, becomes kam. Sometimes the inverted form is smoothed out to make it more natural sounding, or extra vowels inserted.
Likewise in Victorian English backslang, a cant spoken by market sellers, words and syllables were inverted. A notable remnant of backslang is the word ‘yob’, still very much in use, which was originally a simple inversion of boy (it has come to mean an aggressive, destructive young man; the female form, more recent, is yobette). 
But the most famous example of a slang which uses this technique of inversion is verlan, an argot spoken in France since the early eighties. The name verlan itself is an example: analogously to vesre, it is an inversion of l’envers (‘the reverse’). Unlike Lunfardo, however, syllabic inversion is the essence of the argot, rather than one of various characteristics. Arguably, verlan is therefore not so much a slang as a way to cloak the meaning of words using a one-size-fits-all coding technique.
Common verlan words include:
Teufeur (from fêteur, party person)
Keuf (an abbreviation of keufli, from flic, cop)
Chelou (from louche, weird or suspicious)
Tromé or trom (from métro)
Some verlan words have become so commonplace that they have, in a sense, replaced their original version. This then necessitates a re-verlanification in order to preserve the function of the slang. Thus, meuf (woman, from femme) which eventually found its way into mainstream respectability via the Petit Larousse, was replaced by feumeu – the verlan of a verlan, a kind of back translation.
Likewise, the verlan word beur, from arabe, has been re-verlanified to yield rebeu; this is due to the fact that beur was used to designate first generation Northern African immigrants to France, whilst rebeu refers to their children.
One final example of a slang which uses this technique is called Šatrovački. This is a criminal slang that was spoken in the former Yugoslavia, but has now penetrated mainstream culture, particularly in Belgrade and Sarajevo.
Words are formed by replacing the syllable order. For example: pivo (beer), becomes vopi. However, sometimes one of the vowels is changed to make the new word easier to pronounce or avoid ambiguity. For example, trava (grass, marijuana) becomes vutra instead of vatra, which is harder to pronuounce, and in any case also means fire.
It would be interesting to know if there was some sort of linguistic-anthropological explanation for the prevalence of this technique. Has anyone read anything on the subject??
