Add English (US, alt. intl.)
It's because the cedilla module isn't loaded by default when the locale is set to en, so you have to change the configuration files for gtk to add them:
- Edit configuration files:
sudo vim /usr/lib/x86_64-linux-gnu/gtk-3.0/3.0.0/immodules.cache
sudo vim /usr/lib/x86_64-linux-gnu/gtk-2.0/2.10.0/immodules.cache