Ted R. Supalla, Ph.D., is a Professor of Neurology, Linguistics, and Psychology at Georgetown University Medical Center, and he runs the Sign Language Research Lab, a part of the Center on Brain Plasticity and Recovery. He has published extensively on the structure of American Sign Language and other sign languages of the world. He has served as a consultant to the World Federation of the Deaf, where he participated in publishing a white paper on the status of sign languages around the world. He is also the author (with Patricia Clark) of Sign Language Archaeology: Understanding Historical Roots of American Sign Language. His lab hosts the Historical Sign Language Database (hsldb.georgetown.edu) as a resource tool for public use.