Mail::SpamAssassin::Conf manpage you may stumble upon the description of a variable called
ok_locales. It turns out I didn’t get it right at first.
If you set this variable e.g. as follows:
e-mails written with Cyrillic script, Chinese characters etc. won’t be predetermined to be spam. Instead, this simply activates rules from the CHARSET_FARAWAY “family”. Those have high scores by default, but if you want to eliminate such e-mails, you need to raise those scores even more (through