In SciTE (Scintilla), how can I create Syntax-Highlighting for my own custom language?

I want to create a custom Language, with its own custom Syntax Highlighting. Notepad++, a Windows-only SciTE/Scintilla based text editor, allowed me to create a custom "Language", and now, in Linux, I want to reproduce the same thing. I need(?) to use **SciTE/Scintilla** because (as far as I know) it is the only plain-text editor which can display ***different size*** fonts in the ***same*** text-file (e.g., default-font= 12pt, comment-font=24pt). I used the **comments** font to display a complex script (alphabet) in a larger font. Please let me know if there is any other **plain-text** editor which does this. I assume this is a feature of SciTE/Scintilla (and not of Notepad++). Some of the magic is possibly (probably?) done in files such as: /usr/share/scite/.properties Notepad++ has a GUI interface to set up a new language or syntax, but I could use some direction on exactly how to go about it in SciTE. Thanks...