If the page contains chunks of text written using different languages such as English, French, or Spanish, then every chunk should be contained in a tag with a LANG attribute.

Clearly identify changes in the natural language used in the text of a document and any text equivalents as follows:

• Identify chunks of text written using different natural languages
• Add a LANG attribute to the innermost element containing the text for each chunk identified previously

If you use different natural languages on a single page, make sure any language switch is clearly identified with the LANG attribute.

Identifying language switches on a page is important for the following reasons:

• Users reading the document in Braille will be able to substitute the appropriate control codes (markup) where language changes occur to ensure that the Braille translation software will generate the correct characters (accented characters, for instance)
• Speech synthesizers that speak multiple languages will be able to generate the text in the appropriate accent with proper pronunciation. If changes are not marked, the synthesizer will pronounce the words in the language it works in, usually producing sounds that cannot be understood
• Users who are unable to translate between languages themselves will be able to have unfamiliar languages translated by machine translators

It is also important because more and more sites will be accessed through audio-only devices such as telephones.

The LANG attribute may be helpful in many other situations, such as the following:

• Assisting search engines
• Helping a browser select glyph variants for high quality typography
• Helping a browser choose a set of quotation marks
• Helping a browser make decisions about hyphenation, ligatures, and spacing
• Assisting spell checkers and grammar checkers