The strongest muscle in the human body, the tongue is our sole muscle connected only on one end. Like an octopus arm, the tongue contains no skeletal support and uses its many muscle groups to contract, lengthen, bend and twist.
Khalil Iskarous is putting that comparison to good use.
Iskarous, who studies how the tongue’s motion is organized while speaking, recently received a $1 million National Science Foundation grant to compare the tongue during speech to a moving octopus arm and the wriggling of the worm Caenorhabditis elegans. By studying communication, locomotion and manipulation, his team will learn the basic principles of animal movement.
The project takes him to USC Dornsife’s Philip K. Wrigley Marine Science Center on Catalina Island, where he photographs octopus arm movements and compares them with ultrasound images of tongues in motion.
By investigating how the tongue behaves in swallowing versus speech, and determining how similar muscular systems serve purposes other than communication, Iskarous hopes to gain insight into the way language differs from other skills in tongue usage.
“Some dialects differ from one another by a couple millimeters here and there of the movement of the tongue,” said Iskarous, who also studies endangered languages. “You can tell when a person is from Chicago or Pittsburgh. We need this kind of flexibility that the tongue gives us.”
Iskarous is also interested in the effect of Parkinson’s disease on speech. Scientists have started using the worm C. elegans as a model for studying this disease.
“We can gain a deeper understanding of higher organisms by studying the simpler ones that have the same principles of movement,” he said.
Iskarous and his team will build on this work, analyzing similarities and differences in how the disease affects movement in organisms as different as worm versus human.
“It’s a truly fascinating thing that we take for granted, the tongue. We just wake up, open our mouths and talk.”