This tool founded only one missing string. Im sure there must be more of them? :D // This should be left alone
define( 'DEFAULT_LANG_DIR', 'cache/lang_cache/1' );
// This is the one you might want to change
define( 'CUSTOM_LANG_DIR', 'cache/lang_cache/2' );
1. english
2. finnish
edit: seems this tool isnt needed anymore?
http://community.invisionpower.com/topic/309492-ipb-31-lang-files/page__view__findpost__p__1950083