In my computer, I have 4 languages installed.
Because of that reason, it's getting rather tedious switching between
all the languages with Alt+Shift until I reach the right language.
After a short research online I discovered that there's a command that does that.
To that command I can attach a shortcut (on XFCE via Menu>Settings>Keyboard>Application Shortcuts)
The command is
setxkbmap -layout us
where the "us" stands for english-us.
(the same names in the "layout" column on "keyboard layouts")