If you are not a Finnish speaker (like 99,9% of you) you might not want to (re)load Finnish and other unwanted language catalogs during the Plone start up. This is possible for Plone 3.1, as Reinout van Rees explains (found out afterwards).
For your Plone launcher, set environment variables (space separated list)
If your Data.fs is not fresh (i.e. you have an existing Plone instance) there is still one task to do. Go to Placess Translation Service in Zope. Delete all translation catalogs. If there exists a translation catalog entry in ZODB a reload event seem to be triggered even though PTS_LANGUAGES settings is effective. Restart Zope. Maybe this is a bug? Do this on a development box only – this code seems to be quite new. The magic code is in PlacelessTranslationService/load.py.