Interior walls take up precious inside space. You may want to make them as thin as possible, unless they are load bearing and/ or sound barriers.
All the interior partition walls can be partially supported by the main cob walls at the places where they meet. Elsewhere, they can be supported with posts or milled lumber running from the ceiling to the floor. These posts can be buried into the floor or set on top of something to keep them off the ground. The wooden uprights can be used to help support the roof and/or a loft.
Wattle and daub is a name for a type of construction used in many countries for centuries. Walls are made of woven sticks to form a net or mesh, then covered on both sides with a thin layer of cob. This is a way to make thinner interior walls. Thinner walls inside are an advantage because you don't use as much precious space.
The woven sticks can be beautiful room dividers just by themselves.
Interior walls can be made using woven sticks, metal mesh or fencing covered with layers of newspaper or magazine pages dipped in clay slip. (See page 147 for more details.)
2x4 frame walls can be used for interior walls. Because these are so straight and flat, it takes a little imagination to get them to look right with the organic shapes of the cob. Plywood and sheet-rock will take an earthen plaster or thick earthen paint to help them match the cob walls.
Thin cob walls will block the noise pretty well, giving you more privacy between rooms. If the interior walls are not responsible for holding up the roof beams, they can be made as thin as 5 inches at the top with a 1 inch in 3 foot taper. Make some test walls and see how thin you can get away with.
If the interior walls are helping to hold up the roof or the loft, make them thick enough at the place where the roof beams will rest to support them.
Very thin walls can be made out of peg board. The board can be bent to make lovely flowing walls. The plaster squishes through the holes to attach itself to the peg board.