* In the comments, request SVN access to (replace ___ with your locale):
** svn+ssh://svn.mozilla.org/addons/trunk/app/site/locale/___
I'd also recommend subscribing to the rss feed for your locale. You can get to the feeds from [http://viewvc.svn.mozilla.org/vc/addons/trunk/site/app/locale/ viewvc]. When a new string is added, the developers will merge the string into your file and mark it as fuzzy. If you're subscribed to the feed, you'll be notified of the change almost immediately.