Any language the speaker cannot understand, especially with writing unknown to the speaker, sometimes abbreviated as moon. Common in multinational IRC-channels where languages not understood by everyone sometimes are spoken.
Guy: "Ebouillantez les amandes, émondez et faites-les frire dans huile chaude puis concassez-les à l’aide d’un mixeur."
Other guy: "Moonspeak."
Other guy: "Moonspeak."
by trollfish May 15, 2009