Create a file named thunderbird in directory /usr/local/sbin
Set owner to yourself (chown youruser:youruser)
Make it executable (chmod +x thunderbird)
Ok, this is how the file like:
!/bin/sh
export LC_TIME=nl_NL.utf8 # or whatever you want
[ “$LC_ALL” != “$LC_TIME” ] && unset LC_ALL # only necessary if set to something different from LC_TIME
exec /usr/bin/thunderbird “$@”
