"What are the staff doing?"
Translation:Hvad laver personalet?
I can only answer for British English (I'm English) but we normally treat "staff" as if it were plural, because it really means the people who work in a place, and people is plural. (For me, the sentence "what is the staff doing?" is a grammatically correct one, but it would suggest something quite surreal, as a staff is an old word for a stick or walking stick. It would conjure up visions of eg The Sorcerer's Apprentice.) I hope this is helpful.
I'm from the US and from the way most of us view it, the staff IS a group, one singular entity comprised of more than one individual. Though more and more media outlets are inexplicaby switching to the British grammar version. It used to drive me crazy until I realized that it came from across the pond.
Both versions are equally valid then, just depending on which type of English is being used (that's why I'm always careful to specify that I speak British English on here, in case it's different elsewhere). I suppose the important thing is that both should be accepted as correct. It's great having a forum like this so that people can exchange information and impressions. There's the old witticism "England and America are two nations divided by the same language", but now with mass international travel and the internet it's easier to keep in touch with the different types of English world wide.