Ctrl + Shift (or Alt + Shift) is what Windows uses so people migrating from Windows often choose this combination. It is actually a poor choice, because you hav

Ctrl + Shift (or Alt + Shift) is what Windows uses so people migrating from Windows often choose this combination. It is actually a poor choice, because you have to remember which layout is selected and make mistakes, so you type something in the wrong layout, notice it and have to delete and retype it again. A better solution is to use non-modal layout switching, when you have a dedicated key for every layout. On Windows I use left and right Control keys (with a help of a closed-source program), so I always start typing with pressing one of them. But on Linux I cannot use them (I tried to write a program that would listen to /dev/input but found out that you cannot switch layout in Wayland-based Gnome from an external program because there is no API for this). Super + Space which is used on Macs, is also a poor choice. It is surprising that Apple, which manufactures it own hardware, was unable to just make dedicated keys for different layouts.