I recently installed and Antergos and when Gnome started up the UI elements were shown in German. When I tried to change the UI Language there were no other languages than German available

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But don’t worry, this can be easily fixed as described very well in the ArchLinux Wiki by simply enabling the required languages in the file /etc/locale.gen

[[email protected]]$ sudo locale-gen
Generating locales...
de_CH.UTF-8... done
en_US.UTF-8... done
es_AR.UTF-8... done
Generation complete.

Now you can choose the selected languages

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