The Alternative dictionaries are a collection of various forms of “bad language” from many languages. At the moment, there are 2743 entries in 162 dictionaries. This is a collaborative project with contributions from a lot of people. The pages are developed and edited by Hans-Christian Holm.
Who knows, this may come in handy someday. They have listed dozens of languages but there are only entries for the ones you might expect– English, Cantonese, Hungarian, Belarusian, Hindi, a few from Afrikaans, and so on.
Here’s a vivid entry from Indonesian: “makan cacang kulit To literally “eat peanuts made of skin’: to perform cunnilingus.” If you know how to pronounce that, leave me a comment (hopefully with a sound file).
According to the home page a new entry system– something wiki-like, one hopes- is being implemented soon. It does look a little unattended. So if you know a few cuss words from, say, Javanese, go for it.