Version: WCAG 2.0 and up
Number: 3.1.2
Level: AA
  • Text

The human language of each passage or phrase in the content can be programmatically determined except for proper names, technical terms, words of indeterminate language, and words or phrases that have become part of the vernacular of the immediately surrounding text.



The purpose of this success criterion is to ensure that reading systems and assistive technologies can detect changes in the language to optimize the rendering of the text (e.g., to optimize text-to-speech playback).

How to Meet

Authors need to ensure that any changes in text are reflected in the language metadata both in the EPUB Package Document and in individual HTML and SVG content document. The xml:lang and lang attributes are used to indicate changes, as appropriate to the format.

Note that this requirement does not require every word not in the default language to be identified. Names, technical terms, and foreign expressions that have become common to the language, for example, are not covered by this requirement.

Additional Information

The following knowledge base pages provide more information about how to address this success criterion for publishing content: