tip: apex of tongue, most anterior part blade: lies right in back of the alveolar ridge dorsum (body): main mass of tongue in front of the root root: most dorsal part of tongue.
Bring milk, water and celery root to a simmer in a large saucepan over medium heat. Reduce the heat to maintain a gentle simmer and cook until very tender, about 30 minutes. Reserve 1 cup of the cooking liquid, then drain. Puree the celery root, butter, salt and pepper in a food processor (or blender) until smooth and the consistency of thinned mashed potatoes.
This is one of the most comforting ways I know to eat celery root. You can simply mash it with a regular potato masher, but for the silken puree that is one of celery root's side benefits, the food processor is the way to go.