IETF language tag

An IETF language tag is a standardized code for a language. These codes also allow to specify language variants and other information. That way, it is possible to say that what is wanted is German, as it is spoken in Austria. The languages themselves usually have codes that are two or three letters long. Certain languages can use more than one writing system: Serbian language can be written with the Cyrillic script, there is a version that uses Latin script, and there is a version that uses Braille script.