"¿Nunca has hablado con mi hermana?"
Translation:You have never spoken with my sister?
I would say that "have you ever spoken with my sister?" would be a perfectly fine translation as that is how we would usually say it in English.
The sentence with "ever" would probably be a more common thing to ask, but it's not a correct translation.
"Have you ever..." is quite neutral. The person just want's to know whether you have spoken with the sister at any time.
But using "never", the question is more loaded, and potentially rhetorical. The person is probably surprised that this is something that has never happened.
Is there anything in this audio to indicate it's a question? I thought it was a statement until I submitted my answer.
I agree. I listened a few times and I don't detect any inflection that would make me think this was a question.