It looks as though Pyphen has full support for arbitrary user-specified hyphenation dictionaries via its filename parameter, but Weasyprint isn't presently making use of that capability. It would be nice to have a commandline switch to specify this option, like with stylesheets, in case people want to do something a bit unusual. At present the only way to tweak hyphenation policy at this level is to maually tweak the contents of the Pyphen package, which is a bit dicey.
It looks as though Pyphen has full support for arbitrary user-specified hyphenation dictionaries via its filename parameter, but Weasyprint isn't presently making use of that capability. It would be nice to have a commandline switch to specify this option, like with stylesheets, in case people want to do something a bit unusual. At present the only way to tweak hyphenation policy at this level is to maually tweak the contents of the Pyphen package, which is a bit dicey.