Hi Kasia,
Thanks for checking. I did figure out that I can use the Polylang plugin and it will allow the units module to load (although I do prefer Qtranslate-x because it simplifies the content creation steps).
While I understand this is a free plugin (and I am very thankful there are plugins like this available to the community), I am a little disappointed that multilingual capabilities get overlooked by so many great plugins out there. It is a completely untapped opportunity for increasing revenues for companies like yours by opening up to other people and regions who do not speak english natively (and trust me, it can be a huge opportunity). Hopefully, it is something you will consider implementing in a future release.
Thanks again for your help. I appreciate all of the great work you are doing for the WordPress community!
Keith