I noticed Sudowrite could handle non-English leads just fine, with one caveat. It seems to ignore most of the non-English characters, so I needed to threw in some English sentences for it to think there are enough contents. But once it starts writing, it follows the non-English contents just fine (sometimes it would return errors, but in many cases it can just keep writing). Would be good to fix the bug so I don't have to use the workaround.