Dublin Core : Language
Either the 2 letter (ISO 639-1) or 3 letter language codes (ISO 639-2) are used in the DAI. At this point, both values are used. A single code should be chosen and made consistent within each collection.
Both coded values are indicated in the Library of Congress Language Code Chart.
639-2 is generally preferable due to the fact that the list is more extensive and they are equivalent with values used in library cataloguing.
|Language||ISO 639-1 Code||ISO 639-2 Code|
The code is often capitalized (Eng as opposed to eng), but need not be.