Mother-in-law languages
From Freepedia
Mother-in-law languages or avoidance languages are a feature of many Australian Aboriginal languages whereby in the presence of certain socially determined relatives it is taboo to use everyday language, instead a special language must be used.
Mother-in-law languages derive their name from the fact that they are commonly used when the speaker is in hearing distance of mothers-in-law and in general of cross-gender parents-in-law and cousins. Mother-in-law languages tend to have the same phonology and grammar as the standard language they are a part of, but the lexicon is often quite different. Mother-in-law languages, however, tend to have a somewhat smaller lexicon than regular languages, having only to do service when conversation with the taboo relatives is absolutely necessary.
For instance, in Dyirbal there is the regular language (called Guwal) and the mother-in-law language Dyalngui consisting of a special set of lexical items that are substituted for Guwal words in the presence of opposite-sex parents-in-law, opposite-sex children-in-law, and opposite-sex cross-cousins. These words are fewer, however, and their meanings tend to be much more generic, e.g. the Dyalngui verb bubaman does service for the Guwal verbs baygun "shake", dyindan "wave" and banyin "smash".
