The BitchX scripting language was oiginally based on that of EPIC, which in turn was (is) a script that extends the ircII IRC client. BitchX is written in C, rather than being an ircII script, and has a lot of extra features, but if you have written scripts for ircII or Epic you should feel at home.
The best way to get started is with /bhelp and /ehelp. if /ehelp doesn't work, make sure the BitchX help is installed, as it contains the scripting manual!.
These Web pages contain documentation for each of the BitchX functions, some of which is taken from the existing help and some from comments in the source and some from reading the code.
I have sorted the functions into approximate categories to try and make it easier to find what you want. If you want more examples or fixes, send a picture of your naked ankles to liam at holoweb dot net and I'll see what I can do. However, I don't maintain these pages very much now; BitchX has /ehelp which is more complete and more useful in most cases.