:language message en_US.UTF-8
locale -a doesn't report the locale en_US.UTF-8: $ locale -a C C.UTF-8 POSIX
en_US.UTF-8 in /etc/locale.gen: $ sudo sed -i '/en_US.UTF-8/s/^# //g' /etc/locale.gen
$ sudo locale-gen … $ locale-a rene@tq84-vm:~$ locale -a C C.UTF-8 POSIX en_US.utf8