We had the same problem in the past and we noticed there was an extra line in the .bashrc file of Ubuntu: 

export FS_DISABLE_LANG="true"

Deleting this line solves the problem. 

The .bashrc file should contain only the following FS lines:

#Freesurfer:
export FREESURFER_HOME=/usr/local/freesurfer
source $FREESURFER_HOME/SetUpFreeSurfer.sh

Make sure you do this for home and root .bashrc files.

Hope this helps.

Best wishes,

Marina