The Australian Standard Classification of Languages (ASCL) has a three- level hierarchical structure. The most detailed level of the classification consists of base units (languages) which are represented by four-digit codes. The second level of the classification comprises narrow groups of languages (the Narrow Group level), identified by the first two digits. The most general level of the classification consists of broad groups of languages (the Broad Group level) and is identified by the first digit. The classification includes Australian Indigenous languages and sign languages.

For example, the Lithuanian language has a code of 3102. In this case 3 denote that it is an Eastern European language, while 31 denote that it is a Baltic language. The Pintupi Aboriginal language is coded as 8713. In this case 8 denote that it is an Australian Indigenous language and 87 denote that the language is Western Desert language.

Language data may be output at the Broad Group level, Narrow Group level or base level of the classification. If necessary significant Languages within a Narrow Group can be presented separately while the remaining Languages in the Narrow Group are aggregated. The same principle can be adopted to highlight significant Narrow Groups within a Broad Group.