when I open a tty (Ctrl + Alt + F1) it doesn't have utf-8 support. How can I enable it?
There is a program
The Linux kernel maintainers do not accept patches for better Unicode support on the console because the console is to be used as an emergency interface. What needs to be done is write a terminal emulator for the Linux framebuffer that undertakes the support for Unicode. Something like a 'getty' replacement. This aspect of open-source development did not receive yet much attention.
Another deficiency with the existing Unicode of the Linux console is that you cannot use dead keys.
YOu should install console-data package If you already install this package, reconfigure it using
And select correct keyboard disposition.