Now in my head-cannon, though I could be wrong, all ships with cognisant gravity drives, at least those old enough that don't need the equivalent of "childcare", usually are able to speak, not just via mind touch, but also via sound. And those that were not given "voices" are still able to talk to others when needed via multiple screens throughout the ship where it can use written words to communicate with others. Not just the Nae'hyn and the Listeners, but also any crew or passengers on board if needing, or wanting, to.