Hypersmurf said:
Without muscles, tendons, ligaments...? How does it do that?
-Hyp.
Well let's see what exactly we are working with here first, these are the parts I read to come to that conclusion:
"You grant the semblance of life and intellect to a corpse, allowing it to answer several questions that you put to it."
So it's clear that you can ask the corpse a question and it will answer the question, by any method ('the spell
allows the corpse to answer several questions'). Given that the corpse is given a semblance of life we can imagine that the corpse has a limited capacity for movement, such as speaking, moving it's mouth and jaw, etc.
"...but the body must be mostly intact to be able to respond."
A skeleton if 'mostly intact' should be able to respond to questioning, by technicality. Though missing all if it's flesh may not count as being 'mostly intact' as long as the skeleton was completely whole it probably counts I imagine otherwise we likely wouldn't see the whole: "You can cast this spell on any corpse that has been deceased for any amount of time". So a skeleton can indeed respond to questioning.
"A damaged corpse may be able to give partial answers or partially correct answers, but it must have a mouth in order to speak at all.
While we can get away with calling a full skeleton moslty intact, I doubt we can get away with calling the skeletal corpse undamaged. So the skeleton will be answering with 'partial answers or partially correct answers'.
A skeleton doesn't possess a mouth by definition: "Mouth: The cavity lying at the upper end of the alimentary canal, bounded on the outside by the lips and inside by the oropharynx and containing in higher vertebrates the tongue, gums, and teeth." So a skeleton cannot speak the answers to questions.
Though as we see in the first quote, a corpse, even a skeleton is allowed to respond to questions (in this case 'partial answers'). Without speaking the corpse could only trace answers in the dust with bony fore-finger (or point, as with a question of "which way to go", etc.) or nod it's head up and down, or side to side, in response to questions. In other words, yes and no.