Edit via sudo gedit /etc/default/locale the default language.
Local code you will find in: /usr/share/localechooser/languagelist; for instance: nl_NL.UTF-8
For AbiWord you will need Ispell and the idutch voor spellingcontrole.
For interfaces: language-pack-gnome-nl
Change English keyboard to us by saving us as gb in
There's a much easier way to set up support for other languages than
English, in particular multi-byte languages like Chinese, Korean or
Japanese: install the package "language-selector", either with
Synaptic, or with the command
sudo apt-get install language-selector
Once it's installed, you can call it with the (confusing) command
Use the "Install/remove languages" button at the bottom to add whatever languages you want, and check the box that says "Use input method engines (IME) to enter complex characters". You can install fonts, dictionaries etc automatically this way, and set your system's interface to your choice from the languages you have installed