Listing sites that concern themselves with made-up playful languages and jargons occurring in all parts of the world. These will often -- but by no means exclusively -- be used by children as a form of code or a game. These languages are characterized by systematic rearrangement of letters or phonemes of words. Play languages are also called ludlings.
Part of the schedule of lectures and assignments of Linguistics 001. Covers language games, song and verse. Includes a section on Ubbi Dubbi and children's language games in a number of countries. http://www.ldc.upenn.edu/myl/ling001/games.htm
Mailing list posting mentions several play languages from different cultures, including Ubby Dubby and one used by natives of central Australia. http://www.linguistlist.org/issues/2/2-406.html
Mailing list posting author Trey Jones presents a summary of secret and play languages from many cultures, including Cazarny Talk, the Russian Fufa Language, Arabic language play and Bengali Pig Latins. Extensive bibliography. http://linguistlist.org/issues/5/5-812.html
