Sorry for the post, I should have asked Google first... I found it:
http://docs.locusmap.eu/doku.php?id=manual:user_guide:maps_locusmaps&s[]=map&s[]=language#map_language
http://docs.locusmap.eu/doku.php?id=manual:user_guide:maps_locusmaps&s[]=map&s[]=language#map_language