locale on linux
first check what's set:sudo locale
second create the missing one with:sudo locale-gen "en_US.UTF-8"
third:sudo dpkg-reconfigure locales
source: https://askubuntu.com/questions/162391/how-do-i-fix-my-locale-issue
Also, if you have issues to use german Umlaute (äüöÄÜÖß) which is not show in the colsole, try to edit /etc/inputrc
# Turns off 8th bit stripping
set convert-meta Off