Hello,
I'm afraid that this feature is not related to HikaShop which is an e-commerce solution for Joomla. It might be the main reason why you can't find any thread in our forum about that.
You should take a look at other Joomla plugins/components to find that feature related to the language management.
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.