I would like to show the captures I took to help if you find yourself in this situation:
I must to explain this:
I set English as default language at installation with an Spanish input, and there is no problem with Spanish keyboard, but to add another i.e. latam (latin-america spanish) you will probably have to add it as described in debian.org guide.
Important Note: I'm not totally sure if it is available in English (or your native language chosen at installation) as described in the 2nd picture, so first check.. but if it's not available proceed as described on the guide above. Then, once available follow as describe below:
Important Note: If you find any trouble like this
"Failed to start Set console font and keymap" in your log you could do this:
`apt remove --purge console-setup` <br/>
`apt install console-setup` <br/>
`dpkg-reconfigure console-setup` <br/>
Appointed by andrzej1_1 in his answer to: "System will not boot after reconfiguring keyboard-configuration and installing console-setup"
Fortunately I've had not this problem (exactly) but... It's something to keep in mind.
Nowadays (July 2017; Debian Stretch with Gnome 3.22.2)
This is the wrong way:
And this is the right one:
Please note that the keyboard-layout in your login screen will change to the chosen once you run the commands as root, so if you want another you would have to add manually (choose the available).
Remember you can switch between the keyboard-layouts available with
space. In case you have multiple keyboard configured available: this means, you could not switch to another keyboard if you have i.e. just English as input