KLyX is a very good WYSIWYM ( What You See Is What You Mean) Text editor. It should be good for any age for writing anything from letters, to short stories and for later years writing essays and such. KLyX is a KDE app, but it is based on LyX, which is a more generic X-based version. The differences are minimal. Just the GUI uses different libs.
LyX comes with an excellent tutorial and help structure. The documentation is the best I've seen for ANY software on any O/S! For the younger audience, they can just start typing away and see the result with a ps or dvi preview. The sections can be selected from a pull-down menu for easy formatting and there are a lot of tool-bar buttons for most functions. There are a few different document types available and as the child uses it more, they can learn how to create more document types to suit their needs. Being LaTeX based, it gives a good introduction to the TeX based world of text editing in a very easy to use manner. Together with the tutorial and help documents, the child can advance at their own pace until they are ready to move to TeX or LaTeX for a truly professional DeskTop publishing tool.
