Learn Dutch: Deze vertaling mist de nuance van het dialect. - This translation misses the dialect's nuance.

You would use the adjective + te + infinitive structure you are learning. It becomes: Deze nuance is moeilijk te vertalen. The original object (de nuance) becomes the subject of the sentence, and you do not need to repeat it at the end.

In English, we might say 'lacks' instead of 'misses'. Could I use the Dutch verb ontbreken (to lack) here?

Yes, but it requires a different sentence structure because ontbreken is intransitive and doesn't take a direct object in the same way. You would say: De nuance van het dialect ontbreekt in deze vertaling (The nuance of the dialect is lacking in this translation).

Because nuance is a French loanword, how is it pronounced in Dutch?

It keeps a very French flavor but gets a Dutch ending. The 'u' sounds like the 'u' in minuut, the 'an' keeps its French nasal sound, and importantly, the final 'e' is not silent like in English—it is pronounced as a short 'uh' sound (a schwa).

Why do we use van het dialect instead of a genitive (possessive) case like we occasionally see in older texts?