Hi,
Yes, we are not fluent in the 40 languages that HikaShop propose thanks to his community.
Your issue is because these are new translation keys.
Go in the Languages tab of the HikaShop configuration and edit your Dutch translation file.
There, go at the end of the file and you'll see the english translations that you can translate.
Then, you can use the "share" button in order to share your translations with the community and we'll integrate them on our end so that other Dutch people can see the interface completely translated.
Regards,
Jerome - Obsidev.com
HikaMarket & HikaSerial developer / HikaShop core dev team.
Also helping the HikaShop support team when having some time or couldn't sleep.
By the way, do not send me private message, use the "contact us" form instead.