Tangible symbol systems
Tangible symbols are a type of augmentative and alternative communication (AAC) that uses objects or pictures that share a perceptual relationship with the items they represent as symbols. A tangible symbol's relation to the item it represents is perceptually obvious and concrete – the visual or tactile properties of the symbol resemble the intended item. Tangible Symbols can easily be manipulated and are most strongly associated with the sense of touch. These symbols can be used by individuals who are not able to communicate using speech or other abstract symbol systems, such as sign language. However, for those who have the ability to communicate using speech, learning to use tangible symbols  does not hinder further developing acquisition of natural speech and/or language development, and may even facilitate it.