[2][3] However, other authors, such as Beukelman and Mirenda, use the term to exclusively describe three-dimensional physical objects that display concrete properties such as shape or texture.
[4] According to Rowland and Schweigert, "for some individuals, the use of tangible symbols may be used to bridge the gap between gestural communication and the use of formal language systems.
[3][5][6] Many authors have also used picture symbols, such as line drawings and photographs to develop language in individuals with little or no speech and/or cognitive disabilities.
For example, learners that are unable to speak can simply point, touch, pick up, or look (in cases of severe motoric impairment) at the object to answer a question or make a request.
[2][3] Finally, three-dimensional objects can be distinguished from one another using touch, and therefore they are suitable for people with visual impairments or blindness.
The tangible symbols can placed in front of the user within reach, placed on a board for visual scanning, or placed in a book for access.
It is important to utilize frequently occurring and highly motivating symbols in order to optimize opportunities for use.
Following the survey, an advisory board consisting of directors of the New York City schools, speech-language pathologists, the designer and manufacturer of the symbols, a representative from the Perkins School for the Blind, college professors, and a graduate research assistant reviewed and discussed the results.