Windows 10 Offline Language Packages Installer V1.5 -v1903
Reboot the machine. Go to Settings > Time & Language > Language . You should see your installed languages. Click on one and select "Set as default" .
If you are looking into using this tool based on the article, here is the trade-off analysis: Windows 10 Offline Language Packages Installer v1.5 -v1903
The author usually dictates how "hacky" the tool is versus how clean the implementation is. Reboot the machine
You must supply your own .cab language files, which can be extracted from a Windows 10 v1903 ISO’s sources\langpacks\ folder. Time & Language >