I think the question marks mean that the typeface doesn't understand the character being used. It "shouldn't" happen, because the typeface is supposed to have all usable characters represented. But there are a lot of characters to cover, so it's not surprising. Thank you for reporting this, hopefully someone will fix it but unfortunately there is usually very low activity here toward improving translations and language files.
If you wish to contribute any language work, we'd be very happy to receive it! The dev team is currently seeking more translators and perhaps also typeface specialists.