6 secret languages

A cryptolect is a secret language used only by members of a group, often used to conceal the meaning from those outside the group.

Here's the SIX SECRETIST LANGUAGES! (Kidding. I figured lists are good for traffic.)

1. Thieves' cant was a secret language which was formerly used by thieves, beggars and hustlers of various kinds in Great Britain and to a lesser extent in other English-speaking countries. The classic, colourful argot is now mostly obsolete, and is largely relegated to the realm of literature and fantasy role-playing, although individual terms continue to be used in the criminal subcultures of both Britain and the U.S.

2. Shelta is a language spoken by parts of the Irish Traveller people. It has been suggested that the word "Shelta" itself derives from the Irish word "siúlta", meaning "of walking". This refers to the nomadic lifestyle of the Travellers, and the fact that they were commonly called "the Walking People".

3. Carny. Note: Though these terms are traditionally part of Carnival jargon, it is an ever changing form of communication and in large part designed to be impossible to understand by an outsider. Thus, as words are assimilated into the culture at large, they lose their function and are replaced by other more obscure or insular terms.

4. Barallete is employed by the traditional knife-sharpeners and umbrella holders (afiadores e paragüeiros) of the Galician province of Ourense. (Yes, those words are real.)

5. Klezmer-loshn (Yiddish: Musician's Tongue) is an extinct derivative of the Yiddish language. It was used by travelling Jewish musicians, known as klezmorim (klezmers), in Eastern Europe prior to the 20th Century.

6. Leet (written as 31337, 1337, and l33t), is used primarily on the Internet, but becoming increasingly common in many online video games. It uses various combinations of alphanumerics to replace proper letters.