Of the 6,909 languages which have been catalogued by linguists, 130 are classified as Deaf Sign Languages. While there are some who question whether or not sign languages are true languages, linguist John McWhorter, in his book The Power of Babel: A Natural History of Language, writes:
“Sign languages are ‘real’ languages just like spoken ones, with grammar, complexity, and nuance; second-language speakers even contrast markedly with native ones in regard to fluency, thus having an ‘accent’ in their sign language.”
Deaf sign languages are not “primitive” or “simple” or “limited” forms of communication. In his book The Origins of Grammar, James Hurford writes:
“It ought to be obvious, but often is not, that a language whose output modality is movements of the hands, arms, head, and face-parts can in principle be just as expressive of ideas of all sorts as a language whose output modality is movements of the vocal cords, tongue, velum, jaw, and lips.”
Sign languages are rule-governed linguistic systems, which means that like spoken languages they have grammar, semantics, syntax, morphology, and phonology. While we generally think of phonology with regard to spoken sounds, in sign language, which is a visual form of language, phonology is about the types of visual signs which are used in the language.
In the brain, one of the characteristics of language is lateralization (the division of the brain into two parts) in which the left hemisphere controls much of language production. In his chapter in the Handbook of Human Symbolic Evolution, Charles Peters reports:
“The left hemisphere is dominant for sign-language, even though processing sign-language involves processing spatial relations at all linguistic levels. Furthermore, the right hemisphere shows complementary specialization for visuospatial non-language functions, even when these appear within the signed sentences themselves as the topographic representations of actual spatial relations.”
Part of the evidence for deaf sign language as a true language can be seen in the fact that signing emerges among deaf children in a fashion similar to the way in which spoken language emerges among hearing children. Stephen Anderson, in his book Languages: A Very Short Introduction, writes:
“This suggests that humans have a ‘linguistic nature’ which asserts itself even in inadequate environments, and that language is a by-product of the developing brain regardless of modality.”
Anderson also points out:
“The course of acquisition of a signed language is also just like what is observed in children learning a spoken language.”
In Nicaragua, about 50 deaf children were placed in a special education program in 1977. Over the following years the enrollment increased, particularly when the Sandinista government established a vocational school for the deaf in 1980. There was no instruction in a signed language, such as American Sign Language (ASL) as there were no qualified instructors available. Basic teaching was done in Spanish. Stephen Anderson reports:
“Before long, however, the teachers observed that the children were communicating with one another by manual gesture. Far from representing simply a failure on their part to learn Spanish, what was happening was that the linguistic richness of the children’s home signing was growing rapidly through interchange with others.”
Chip Walter, in his book Thumbs, Toes, and Tears and Other Traits that Make Us Human, reports it this way:
“But the children did have an overwhelming desire to communicate. And so they did something extraordinary. They began to talk among themselves, using their hands.”
Chip Walter goes on to report:
“And what makes it truly amazing is the children managed this on their own without any central planning. No one sat down and wrote a grammar or created a dictionary. No one developed or taught a course. The language simply emerged naturally, out of the interaction of the children as they struggled to share what was on one another’s minds.”
Within a few generations, a complex sign language—Idioma de Señas de Nicaragua—emerged. Those who became most fluent in the language were children who came to the school before the age of seven. As more children acquired the language it developed further, and the children who arrived after the language had been used for a decade became most fluent. According to Stephen Anderson:
“This language is quite independent of other languages, signed (like ASL) or spoken (like Spanish), and now serves for its users as a vehicle of communicative expression like any other.”
With regard to the rapid evolution of sign language among the Nicaraguan children, James Hurford writes:
“What is most striking about this language is the fact that deaf children, within the space of about a decade, created a full-blown sign language with its own syntax. What concerns us here, which is implicit in the first fact but less remarkable, it that the children also spontaneously developed their own common vocabulary of lexical signs.”
For those interested in the origins of language, the evolution of the Idioma de Señas de Nicaragua provides an interesting example of language origins as it allows us to see the process of language creation from scratch. James Hurford writes:
“The child inventors of Nicaraguan Sign Language are the closest we have to people who have created a new language from scratch, without learning it from any external source.”
The implications of this for understanding the origins of language, according to James Hurford;
“Clearly for modern humans, given the right social conditions, and a population of young people, the spontaneous emergence of a shared lexicon from scratch is possible and, we may even say, straightforward. At some era in the past, our ancestors had evolved to a stage where such vocabulary-creation became possible.”
Another distinct sign language is Hawaii Sign Language which linguists have determined is a distinct language: it is not a dialect of American Sign Language. It has a unique vocabulary and grammar. While the language dates back to the 1800s and possibly earlier, today there are only about 40 people who currently use Hawaii Sign Language. Most of those who use it are in their 80s which means that the language may be facing extinction.
Inuit Sign Language (IUR) evolved in the Arctic region of Nunavut. Historically, sign languages were used as a type of trade language to facilitate communication between Inuit groups with unintelligible language or dialects and as a silent language used during group hunts. In his chapter in Sign Languages in Village Communities: Anthropological and Linguistic Insights, Joke Schuit reports:
“Due to unknown reasons, a rather high percentage of Inuit were born deaf or became deaf. The signs already existing in Inuit culture probably were used with the deaf children and then evolved into a language.”
In sign languages, the hands—the handshapes—are an important part of the communication system. In the Arctic, extreme cold means that hands are usually covered. Joke Schuit reports:
“Informants reported that messages tend to be short when communicating outside in cold weather. People wait until they are back in the house before expanding the conversation. The climate therefore seems to have affected IUR mainly pragmatically, but not phonetically.”
Another historic example of deaf sign language is found in New England. In his book Hand Talk: Sign Language among American Indian Nations, Jeffrey Davis reports:
“For more than 250 years, both deaf and hearing inhabitants of the island reportedly used sign language for everyday communication purposes. Martha’s Vineyard was an example of a pre-industrialized community where sign language was handed down from one generation to the next.”
There are several possible sources of the Martha’s Vineyard Sign Language. The aboriginal inhabitants of the Island were the Wampanoag who used an Indian sign language as both a trade language and a deaf language (there was a great deal of inherited deafness on the island.) Jeffrey Davis writes:
“It is unknown if these Native Americans were a source for the sign language that was eventually widely used by both deaf and hearing populace of the island.”
On the other hand, many of the English on Martha’s Vineyard came from Kent, where the Old Kent Sign Language (OKSL) was commonly used. It is therefore possible that OKSL was the source of the Martha’s Vineyard Sign language, or that both OKSL and the Wampanoag sign language were used to form the new language.
With regard to the neurological basis of language, Stephen Anderson writes:
“The implementation of signed language in its users is also entirely parallel to the way spoken languages are housed in their speakers. Signers show activity in the same brain regions (apart from effects due purely to differences in motor control of the specific organs involved) as speakers.”
Deaf sign languages are not merely forms of pantomime. The sign for tree, for example, given in ASL is totally different and incomprehensible to the sign for tree used in other deaf sign languages. Just as spoken languages in different parts of the world are mutually unintelligible, sign languages in different parts of the world as also mutually unintelligible.
Another common misconception is that deaf sign languages are somehow based on spoken languages. Stephen Anderson writes:
“Signed languages are also not just an alternative expression of the spoken language of the surrounding community—the two are quite independent of each other.”
ASL, for example, derives in part from an eighteenth-century French sign language and is somewhat mutually comprehensible with French Sign Language. On the other hand, British Sign Language (BSL) has quite different origins: BSL and ASL are not mutually comprehensible.
When linguists have traditionally studied spoken languages, they have looked at a number of layers of organization: phonology (the significant sound patterns used in the language), morphology (how sounds are organized into words), and syntax (how words are combined into phrases and sentences). Sign languages have parallels to all of these same levels of organization.
Spoken languages use sounds and sound patterns in forming meaningful utterances. In sign languages, signs can be broken down into distinct components such as handshape, location, movement, and so on. Just as spoken languages use different inventories of sound, sign languages use different inventories of gestures. Stephen Anderson writes:
“While it seems somewhat strange to talk about ‘phonology’ of a language that does not involve sound, the structural similarities of organization of language in the two modalities have led to this as standard terminology.”
Sign languages may also provide some insights into the origins and development of language in our species. Nicholas Wade, in his Before the Dawn: Recovering the Lost History of Our Ancestors, writes:
“Sign languages emphasize an often overlooked aspect of language, that gesture is an integral accompaniment of the spoken word. The human proto-language doubtless included gestures, and could even have started with gestures alone.”
Over the past century, many researchers who have looked at the origins of language in our species, Homo sapiens, have suggested that the origins of spoken language lie in sign languages. In her chapter in The Linguistics of Sign Languages: An Introduction, Anne Baker writes:
“There are even speculations that sign languages were the first form of communication between humans in the pre-historic period—this is referred to as the ‘gestural’ theory of language origin’. In that case, sign languages would have been around before spoken language, and both deaf and hearing people would have used them.”
In his book TheGap: The Science of What Separates Us from Other Animals, Thomas Suddendorf puts it this way:
“Speech involves complicated deliberate motor acts. Great apes have much more voluntary control of their hands, which they use, for example, to extract foods, than over their articulations. If our common ancestor had such control, it would appear easier for natural selection to tinker with such control than for it to invent vocal control de novo. Gestural communication also has the advantage of being more iconic, where words are almost entirely arbitrary. Indeed, some things are much more intuitively communicated by gestures: try to explain to someone what a spiral is.”
The hypothesis that language began with signs before becoming spoken is not a recent one. In his 1918 book Sign Talk of the Cheyenne Indians and Other Cultures, Ernest Seton writes:
“The Sign Language is a system of root ideas expressed by gestures, preferably made only by the hands, without sounds or reference to letters, or words, spoken or written, and not delimited by anything corresponding to words. There can be little doubt that Sign Language preceded all audible speech.”
There are, however, researchers who disagree with the hypothesis of signed language evolving prior to spoken language. This continues to be a topic of debate among linguists, paleoanthropologists, and philosophers.
More Human Origins
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