"All world languages are in scope of the classification. Languages with significant numbers of speakers in Australia are separately identified within the classification structure. Actively spoken Australian Indigenous languages are also separately identified. Languages which are not separately identified are included in the most appropriate residual category of the classification. Extinct or dead languages spoken for religious or academic purposes are included in the most appropriate residual category of the classification. However, if sufficient numbers of an extinct or dead language are spoken in Australia, it is separately identified in the classification, for example Latin. Sign languages are defined as a communication system using gestures rather than speech or writing (The Macquarie Dictionary (Fifth Edition, 2009), and are included in the classification. Languages excluded from the classification cover those not commonly used as a means of communicating between people, such as computer languages."