Here's a suggestion from the meaning of 'translated' and 'localized':
Item A: Original English item
Item B: French version translated from item A
Item C: German version translated from item B
Both items B and C have parent_id pointing to item A with the tag 'localized'.
Additionally, C has a rel with item B with the tag 'translated'.
This means that 'translated' means 'based on this item', while 'localized' means 'is this this item in language X'.
