Have the ability to convert language wikilinks to the {{lang}} template, for example:

[[Arabic language|Arabic]]: ‏ليبيا‎]] -> {{lang-ar|‏ليبيا‎}}

This is most commonly seen at the beginning of articles where it gives the person or place's name in its native language.

The reason to use {{lang}} is given at https://en.wikipedia.org/wiki/Template:Lang#Rationale. However, the most important reason is for accessibility – screen readers need language info to speak text in the correct language – and to satisfy Wikipedia accessibility guidelines. @Bgwhite 21:48, 7 July 2014 (UTC)