Dyirbal, a language of the Cairns rain forest in Northern Queensland, employs a system known as the affinal taboo index. Speakers of the language maintain two sets of lexical items: 1) an "everyday" or common interaction set of lexical items and 2) a "mother-in-law" set that is employed when the speaker is in the very distinct context of interaction with their mother-in-law. In this particular system of deference indices, speakers have developed an entirely separate lexicon (there are roughly four "everyday" lexical entries for every one "mother-in-law" lexical entry; 4:1) to index deference in contexts inclusive of the mother-in-law.