Probably best to see the "Content" sub-forum -
https://www.mobileread.com/forums/forumdisplay.php?f=112
ConverLit GUI includes the command-line ConvertLit (clit.exe)
BookDesigner (note: it's a matter of installing the main app then updates over the top) does have an english UI, but I can't recall what you need to do to select it - an option on first run, I think?