Comment 1 for bug 1826567

Workaround:
Before starting the installation (or after cancelling it during the first steps), click on "Activities" (top left corner of the screen), then type "settings" and press enter to bring up the "Settings" application. There, click on "Region & Language" on the left column menu, then, under "Input sources" click the "+" icon and select the preferred keyboard layout. Then click the trash icon next to the "English" 'input source' to delete this keyboard layout and make the preferred one default. Starting the installer now will make it use the desired keyboard layout both during the installation and on the installed system.