The AGROVOC field module is included in the AgriDrupal package, but can be used out of the box in any Drupal installation. It is available to download at Drupal.org

Multilingual

It has a well integrated multilingual support.

• If one indexes a node, the module lists the Agrovoc terms in the language currently used by the website, but then stores the selected terms in all the languages enabled by the website together with the URIs of the corresponding concepts.
• If one switches to a different language, the corresponding Agrovoc terms will be displayed in that language.
• If one translates a node that has already been indexed, the translated Agrovoc terms will be displayed and the autocomplete field will only list the terms in that language.

Being a CCK field synchronized with a taxonomy, it allows to exploit both CCK and taxonomy features in Drupal. The labels in all enabled languages are stored as taxonomy terms, while the URI is stored in the CCK field.