By default, Chinese text is sorted by radical/stroke elements. Radical/stroke indexing works without sort keys. An alternative sort option based on Pinyin transliteration is also available. The index configuration files for radical/stroke define default collation orders, extended special character sets, and heading structure definitions.

Set the index configuration files using the APTIXLANG environment variable.

The resulting index is sorted by Unicode character code, with a subgroup head for each radical (for example, for each character of the subrange).