ただ，こちらの /etc/fonts/fonts.conf にはこんな設定が入ってます．参考になれば......
<!-- Latin fonts should not be used for ASCII characters when using
Japanese monospace families -->
<match target="pattern">
<test name="family">
<string>monospace</string>
</test>
<test name="lang" compare="eq">
<string>ja-jp</string>
</test>
<edit name="disable_pango_script">
<bool>true</bool>
</edit>
</match>
