Checks whether a field has language support.
A field has language support enabled if its 'translatable' property is set to TRUE, and its entity type has at least one translation handler registered.
$entity_type: The type of the entity the field is attached to.
$field: A field data structure.
TRUE if the field can be translated.
function field_is_translatable($entity_type, $field) {
return $field['translatable'] && field_has_translation_handler($entity_type);
}