The cactacae are Plant People and don't have internal organs, fair enough. They still eat food (which can include human food) with their mouths, though... and how do they speak if they have no lungs?
It could be that their mouths lead to an enzyme-filled cavity like pitcher plants have, or to a colony of symbiotic bacteria like tube worms use. Lots of species can extract nutrients without a regular digestive tract. As to speaking... advanced stomata? careful belching? vibrating their needles in tune?
The long-ago Malarial Queendom was ruled over by female anophelii, who are only capable of coherent, sentient behavior when well-fed. On blood. And it's remembered by other races with so much dread that they marooned the entire race of anophelii on an isolated island. Think about it.
