It all depend on what you count as connotation, but I'd argue that if anything can be expressed verbally, then it can be translated. There is no such thing as untranslatability.
The same way most languages have singular and plural, Slovenian also has dual. It's much handier than always specifying "two somethings". Very few languages still have this feature. English for instance only has residual traces left.
https://en.m.wikipedia.org/wiki/Dual_(grammatical_number)
You can translate it, of course, but it's going to look and feel awkward.
Have you made a serious effort to translate jokes, poetry, or advertising slogans between unrelated languages before you made that assertion? Were your clients unequivocally satisfied with your work?