Secret languages

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

A language game (also called secret language or ludling) is a system of manipulating spoken words to render them incomprehensible to the untrained ear. Language games are used primarily by groups attempting to conceal their conversations from others. Some common examples are Pig Latin, which is used all over the globe; the Gibberish family, prevalent in the United States and Sweden; and Verlan, spoken in France.

Each of these language games involves a usually simple standard transformation to speech, thus encoding it. The languages can be easily mentally encoded and decoded by a skilled speaker at the rate of normal speech, while those who either don't know the key or aren't practiced in rapid speech are left hearing nothing but gibberish.

A common difficulty with language games is that they are usually passed down orally. While written translations can be made, they are often imperfect, and thus spelling can vary widely. Some factions argue that words in these spoken tongues should simply be written the way they are pronounced, while others insist that the purity of language demands that the transformation remain visible when the words are imparted to paper. Contrary to what proponents of either side may say, there is no one definitive written lexicon for language games, but it is rather a matter of dialect.

Use
Language games are primarily used by children, to disguise their speech from others. Some language games, such as Pig Latin, are so widely known that privacy is nearly impossible, as most people at least know how it works, even if they can't speak it themselves. Although language games are not usually used in everyday conversation, some words from language games have made their way into normal speech, such as ixnay in English (from Pig Latin), and loufoque in French (from Louchébem).

Classification
One way in which language games could be organized is by language, for example, Pig Latin, Ubbi Dubbi, and Tutnese could all be in the "English" category, and Jeringonza could be in the "Spanish" category.

An alternate method of classifying language games is by their function. For example, Ubbi Dubbi, Bicycle, and Allspråket all work by inserting a code syllable before the vowel in each syllable. Therefore, these could be classified in the Gibberish family. Also, Double Talk, Língua do Pê, Jeringonza, and B-Sprache all work by adding a consonant after the vowel in each syllable, and then repeating the vowel. Thus, these could be classified in the Double Talk family. Another common type of language game is the spoonerism, in which the onsets of two words are exchanged. Using a standard word for each transformation gives another type, for example, the Finnish "kontinkieli", where kontti is added after each word, and spoonerism applied (kondäntti koonerismspontti koppliedäntti).