Indicate which keyboard layout is active when typing the password on boot-up

I have a feature request: please display to the user which keyboard layout is active when they are tying their password upon boot-up.

I had set up full-disk encryption using Ubuntu's installer. One day, after rebooting, I could not get my new password accepted. I tried again and again. Eventually, I realised that I was typing in the wrong keyboard layout. This requested feature would have saved me so much time and would have enabled me to realise what the problem was much sooner.

Note that there is no way to verify what keyboard layout is active, as whatever you type is hidden with asterisks. Even changing to another virtual terminal does not let you display what you have typed. This makes it even more important to give the user a visual indication of which keyboard layout is active.

I am using Ubuntu 18.04.