LibreOffice automatically detects your operating system language before installation, and will install the language matching your operating system.
If you want to change the language first we need to add more language in the installation options, and then to change the setting.
1. Run the LibreOffice installation file:
2. On the second screen select "Custom".
3. Click on "Additional User Interface Language", locate your language and click on the red X, then click "This feature will be installed on local hard drive".
4. On the next menu tick all the boxes, and continue with the installation.
5. On the last installation menu make sure to choose "Load LibreOffice 18.104.22.168 during start-up".
6. After the installation open one of LibreOffice software and select Tools from the above menu bar. Then click on Options.
7. Click the little + sign to the left of "Language Settings", then on "Language" from the drop menu.
8. On the right side click on "User Interface" and Chose your language from the list. then click "OK" and restart the software.