If you've got help for the language in the windows help format (.chm) or html (see below) you can use windows program hh.exe to open it via a beanshell script. I don't know whether you can pass a parameter = word to search. You can associate the script with a button/menu item.

Note: You can generate .chm from a set of html with HtmlToHlp (search google).
****************** ShowPhpHelp.bsh
void showPHPHelp()
{
try {
Runtime.getRuntime().exec("hh.exe C:\\Program Files\\_programovani\\php\\php_manual_fr.chm");
} catch( Exception x){ x.printStackTrace(); }
}
showPHPHelp();