Language information specified via the lang attribute may be used by a user agent to control rendering in a variety of ways. Some situations where author-supplied language information may be helpful include:
* Assisting search engines
* Assisting speech synthesizers
* Helping a user agent select glyph variants for high quality typography
* Helping a user agent choose a set of quotation marks
* Helping a user agent make decisions about hyphenation, ligatures, and spacing
* Assisting spell checkers and grammar checkers
The lang attribute specifies the language of element content and attribute values; whether it is relevant for a given attribute depends on the syntax and semantics of the attribute and the operation involved.
