I think that one of the universal materials in which to communicate is paper mache. It has been used for centuries by different cultures all over the world. It is relatively light compared to other natural materials. It's malleable wet and very strong when its dry. It's texture, colors, and shapes are both primal and inclusive.
It's laborious, but cheap to produce.
For glue, I make a paste of flour and water, about the consistency of pancake-batter, and I add a little bit of wood glue for super-strength. I use butcher paper and paper grocery bags (recycled). Then paint it with One Shot enamel paint.