The GTKv2 client defaults to French on command output.
New build (from source) of client, maps, arche and server r21053, example output of the mapinfo command:
Museum of Arms (/navar_city/magara/houses/museum) in The Kingdom of Navar
joueurs:1 difficulté:1 taille:52x42 début:5x37 timeout 0
Run the following command: 'language en
(which results in this display: Your current language is set to English.)
The same mapinfo command on the same map now displays:
Museum of Arms (/navar_city/magara/houses/museum) in The Kingdom of Nava
players:1 difficulty:1 size:52x42 start:5x37 timeout 0
A fix was committed in r21059, does this resolve the issue?