Alternatively, spells intended to prevent a corpse from rising as an undead like gentle repose could arguably also block out speak with dead, since it's necromancy. But a magic item recasting speak with dead and using magic mouth to ask nothing questions is pretty inventive solution!. You grant the semblance of life and intelligence to a corpse of your choice within range, allowing it to answer the questions you pose. The corpse must still have a mouth and can't be undead. The spell fails if the corpse was the target of this spell within the last 10 days.
Speak With Dead may work on only skulls. Again, because what exactly constitutes a "corpse" is not explicitly defined in DnD's rules, we're left to our best interpretations.. Dungeons and Dragons (D&D) Fifth Edition (5e) Spell - Speak with Dead - You grant the semblance of life to a corpse of your choice within range, allowin.