Feature request from mage2pro, posted on GitHub Sep 22, 2015

You can translate order statuses manually in «Stores» → «Order Status» admin section.
But it is inconvenient because:
- you must do it manullay for each new Magento installation
- it works for a single language but does not work for multistore Magento installation with multiple languages.
My fix for automatical translation: https://mage2.pro/t/76