We've also seen her effecting technical repairs to the communication console, as in, crawling up underneath it with space-pliers.
I think her job is a technical/sciences one. Not so simple as 'run the radio', to be sure, but there's absolutely zilch about being a linguist, despite what Nichols says. Must I bring up the MLK story that always grew bigger in the retelling?
I imagine Uhura knew a lot about subspace, information theory, encryption, etc.