The ability to speak has been viewed as the most important
factor that distinguishes humans from other animals. Many modern linguists, most famously Noam
Chomsky, have argued that language is, indeed, a unique characteristics of
humans. This is not to say that other
animals don’t communicate – dolphins use whistles to identify themselves and
send information to one another while elephants use trumpeting to call to each
other to signal danger as well as a complicated form of sign language to
communicate intentions, moods and desires.
Yet no naturally occurring language that exists in other animals has the
complexities, flexibility and developmental capacity of human language.
During the early 1900’s, several scientists attempted to
teach human language to chimpanzees but were unsuccessful. It later came to light that this was not due
to the potential of the chimps but to structural differences in ape and human
vocal tracts. This meant the chimps
weren’t able to physically produce the sounds of human language. Later research focused on teaching a non-vocal
language to primates. In the late 1960’s Washoe, a female chimpanzee learned to
use well over 350 signs, learning many spontaneously from observing the humans
around her. Around the same time, others
used tokens that stood for words, teaching the ape’s to arrange them in
different orders. A female chimp named
Sarah learned to produce streams of tokens which obeyed a grammar and could use
if-then-else expressions.
Watch this video, A Conversation With Koko The Gorilla, an
award-winning documentary about an amazing gorilla who learned to converse with
a researcher using sign language.
Then in the 1970’s, Ernst von Glasersfeld developed a
language that researchers first taught to the female chimp named Lana. It was called “Yerkish” after Robert M.
Yerkes, the founder of the laboratory within which the language project was
carried out. Lana was taught to comprehend and use symbols via an innovative
computer-based keyboard.
Yerkish, not to be confused with Yiddish, has developed into
a language used to communicate with nonhuman primates. The language was
initially used to communicate with the primates at the Yerkes National Primate
Research Center in Atlanta, GA. In addition to Lana, Duane Rumbaugh used the
language to communicate with two other chimpanzees at Yerkes. The symbols
represent but are not necessarily exact portrayals of words. A keyboard with a lexigram laid out on the
keys is used by the primates and the researchers. Lexigram boards were composed
of three panels with a total of 384 keys. When pressed, keys would light up and
the associated symbol would be projected on a screen above the keyboard. “Correct” or “legal” sentence resulted in
automatic results. For example, the
sentence “Please Machine Give Juice” would lead to juice being dispensed. Other sentences or questions would be
responded to by human caregivers also using the keyboard.
As this project continued it became clear that keyboard
facilitated learning successfully helped chimps develop language skills. These skills went beyond just learning the exact
associations that were taught to them.
The chimps were able to spontaneously generate novel combinations of
symbols to communicate desires and ask questions along with answering questions
and completing assigned tasks from researchers.
There are those who say that there is no reason to waste
time and money trying to teach human language to apes. Yet the language project with apes provided
the foundation for creating communication boards and keyboard facilitated language
development devices for use with non-verbal children with autism. This further
led to developments in speech assistive technology that has proven to be invaluable
for those with autism who have trouble learning vocabulary and grammar, don’t
understand the social rules for conversations, or have difficulties
spontaneously using spoken language.
View this segment of a video produced for Autism Acceptance
Month of a young man named Dillan who uses technology to convey what the world
is like for him. His words remind us how
important it is to ensure everyone with a voice can be heard.
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