OK, Zorin by default comes with Firefox and whilst you don't have it installed, language packs are a separate bundle so they will come through I guess even if you don't have it installed. If you haven't got synaptic package manager installed, install it from the software channel then open it (you'll need to enter your login password for root privileges to make changes) search for Firefox Language Packs (or just Language Packs) then click on the 'S' at the top of the 'S' column and all installed language packs will be arranged at the top of the window - mark each one you don't need for removal and then click on 'apply' to remove them - you should then no longer get any more updates. Also whilst you are at it, ensure that your updates come from 'Main Server' and not your country server where you are based (as stated in the Unofficial Manual for Zorin that I authored).