One of the common mistakes people make is to assume that deaf sign languages are based on spoken languages. In fact, deaf sign languages evolved independently from spoken languages.
As the academic discipline of linguistics—the scientific study of language—began to develop during the nineteenth and twentieth centuries, language was defined as a spoken form of communication. During the nineteenth century in particular, language was viewed through the lens of an early form of cultural evolution in which some cultures and their languages were seen as “primitive”, that is, they belonged to an early stage of evolution. In his book Hand Talk: Sign Language among American Indian Nations, Jeffrey Davis writes:
“In this view, gestures would have preceded speech in the human epoch: thus, sign language was viewed as a by-product of primitive culture.”
During the twentieth century, linguists began to abandon the nineteenth-century model of cultural evolution as they realized that while languages might be very different from one another, there was no hierarchy of languages. However, the focus remained on understanding spoken languages and signed languages were either ignored or viewed as being related to spoken languages.
During the twentieth century, the scientific field of linguistics developed distinct subdisciplines of phonology, syntax, semantics, and pragmatics, as well as historical linguistics, ethnolinguistics, psycholinguistics, sociolinguistics, and neurolinguistics. In all of these, the focus was on language as a spoken medium.
The field of linguistics did not begin to recognize and study deaf sign languages as distinct languages with their own phonetics, grammars, syntax, and unique histories until the last part of the twentieth century. In her chapter in The Linguistics of Sign Languages: An Introduction, Anne Baker reports:
“Until roughly 1980, sign languages were hardly mentioned in any introductory textbook on linguistics. Although linguistic research had been done on sign languages, primarily on ASL, at that time, since the early 1960s, this work had not had any influence on mainstream linguistics.”
The change in focus came about in part via increased understanding of signed languages as well as the influence of Noam Chomsky on the field of linguistics. Chomsky emphasized that language was innate. In his book Darwin’s Dangerous Idea: Evolution and the Meaning of Life, Daniel Dennett reports:
“According to Chomsky, the structure of language is mostly fixed in the form of innately specified rules, and all the child does is set a few rather peripheral ‘switches’ that turn him into an English-speaker instead of a Chinese speaker.”
Daniel Dennett also writes:
“A few developmental triggers set the language acquisition process in motion, and a few environmental conditions subsequently do some minor pruning or shaping into whichever mother tongue the child encounters.”
In her chapter in the Handbook of Human Symbolic Evolution, Carolyn Ristau reports:
“In Chomsky’s view, a necessary characteristic of language is the existence of grammar. The grammar, or system of rules, is biologically based in humans and unique to them: it is a human universal.”
In other words, sounds might be a part of most languages, but language is not defined by sounds. Language is the structure that allows symbols—spoken, signed, or written—to be strung together to communicate about the past, present, and future, as well as the real and the imaginative. Looking at language in this way, linguists came to accept that signed languages are fully developed languages independent from spoken languages.
In his book Hand Talk: Sign Language among American Indian Nations, Jeffrey Davis writes:
“Signed languages have evolved as full-fledged languages, and in some communities have served as alternatives to spoken language—yet another demonstration of the human innateness and resiliency of language.”
In her chapter in The Linguistics of Sign Languages: An Introduction, Anne Baker writes:
“Sign languages were not invented by hearing people nor are they derived from spoken language. Rather, they emerge as the result of natural interaction between deaf people.”
With regard to the common misconception that sign language is based on a spoken language, David Harrison, in his book When Languages Die: The Extinction of the World’s Languages and the Erosion of Human Knowledge, writes:
“American Sign Language (ASL, used by up to 500,000 deaf people as their primary language) is no closer to English in its words, structures, and grammar rules than is Japanese. Another common myth is that signed languages use mostly iconic gestures, meaning hand shapes that look like or mimic the things they refer to, and thus signs can be universal to all deaf people. This is also false.”
In adding signed languages to the field of linguistics, we expand our understanding of language, including the origins of language, in a very broad sense. In his book Through Indian Sign Language: The Fort Sill Ledgers of Hugh Lenox Scott and Iseeo 1889-1897, William Meadows writes:
“Recognizing that human language is not limited to auditory-oral channels but includes equally rich forms such as visual-gestural modes, linguists continue to explore the gradient and semiotic features of human languages to uncover new insights into the complexities of language and the human mind.”
Today, linguists recognize nearly 7,000 spoken languages and at least 200 signed languages. David Harrison writes:
“Most of the world’s signed languages—spoken natively by deaf people—have never been properly counted or documented.”
David Harrison also writes:
“Researchers have demonstrated that sign languages are fully complex, fully functioning human languages, not simplistic gesture systems or in any way inferior to any other human language.”
An understanding of the linguistics of signed languages will add to our overall understanding of language.
Language Acquisition
According to Chomsky, at birth all humans have a “language-acquisition device” which allows them to learn the languages to which they are exposed during childhood. Researchers who studied the Deaf communities observed that children in these communities acquired signed language in a manner similar to the way in which children in hearing communities acquired spoken languages. This is further proof that language, or, more specifically, the ability to acquire language, is an innate human characteristic.
The ability of children to acquire signed languages is seen as additional proof that signed languages are true languages equal in their ability to communicate with spoken languages. In his book Language, Culture, and Society: An Introduction to Linguistic Anthropology, Zdenek Salzmann puts it this way:
“Furthermore, they are natural languages in the sense that their acquisition is the automatic result of interaction with others who depend upon signing.”
In her chapter in The Routledge Handbook of Historical Linguistics, Susan Fischer writes:
“Sign languages arise almost anywhere there are deaf people. By definition, deaf people cannot hear, but most have an innate capacity for language, and language will out one way or another.”
Phonology and Phonetics
In studying spoken languages, linguists often look at phonology (the meaningful sound patterns of the language) and phonetics (how the sounds are produced). In their chapter on phonetics in The Linguistics of Sign Languages: An Introduction, Onno Crasborn and Els van der Kooij write:
“Phonetics studies the physical properties of the process, while phonology focuses on the parts of the words and signs as they function in the system of a specific language.”
In their chapter on phonology in The Linguistics of Sign Languages: An Introduction, Els van der Kooij and Onno Crasborn write:
“Phonology studies those elements used to form words and their possible combinations. In the phonology of spoken languages, the sounds of a specific language are analyzed and how these sounds are combined into syllables and words. Not all languages use the same set of sounds, and not every combination is possible.”
Els van der Kooij and Onno Crasborn go on to report:
“In sign languages, the same distinction applies. It is not possible to do just anything with your hands and for that to be a possible sign in a given sign language.”
With regard to the phonetics of signed languages, Allan Taylor, in his chapter in the Handbook of North American Indians, writes:
“The production of signs can be described in terms that are often analogous to those used in the description of speech. In sign language articulation the analogue of movable articulator in speech—the tongue and lips—is the hand or the hands.”
Allan Taylor goes on to report:
“The analogue of the place of articulation in verbal speech (e.g., the palate, the upper teeth) is the point at which a gesture is made, or to which the hand moves during the gesture.”
Dialects and Languages
In studying spoken languages, most people—both linguists and laypeople—are aware of regional differences in speaking which are known as dialects. In fact, native speakers of one dialect may find some dialects of the same language almost impossible to understand. At some point, dialects diverge to the point where they become different languages, although the distinction between what is a dialect and what is a language is, at times, more political than linguistic. In her chapter in The Linguistics of Sign Languages: An Introduction, Trude Schermer writes:
“Discussions about the differences between a language and a dialect has never led to a clear definition of what constitutes a language and what constitutes a dialect. There are no linguistic arguments that can be put forward for classifying a system as one or the other.”
Trude Schermer also writes:
“It seems as though the differences between language and dialect has more to do with a difference in status. In Western societies, a language frequently has more status than a dialect.”
Linguists who have studied signed languages find that, just as in spoken languages, there are dialects, regional differences in signing. It should be pointed out that while British English and American English are considered dialects of English, that British Sign Language (BSL) and American Sign Language (ASL) are distinct languages. Neither BSL nor ASL are based on English and they have distinct histories. On the other hand, the British-based sign languages—New Zealand Sign Language (NZSL), Australian Sign Language (Auslan), and British Sign Language (BSL)—can be considered dialects of the same language.
Language Families
In historical linguistics, languages are compared and grouped into language families showing the relationships between the languages. Signed languages, like spoken languages, can also be grouped into language families. In their chapter on language contact and change in The Linguistics of Sign Languages: An Introduction, Trude Schermer and Ronald Pfau write:
“Sign languages are not related to or derived from spoken languages, but there are relationships between different sign languages. Current research indicates that there are language families of sign languages, just as there are in spoken languages.”
One of the ways of comparing languages and developing language families is through word lists. Trude Schermer and Ronald Pfau write:
“As in comparative work on spoken languages, a comparative study of lexicons, or a lexicostatistical study, in commonly used to establish the relationship between languages. This method is frequently applied to languages for which there is barely any description.”
There are, however, problems in using the standard word lists developed by linguist Morris Swadish for spoken languages and, therefore, linguists working with signed languages have developed lists which are more appropriate for these languages.
Bilingualism
In today’s literate society, deaf people who are fluent in a sign language are often bilingual in that they can also read the written form of their community’s spoken language. Susan Fischer puts it this way:
“Most users of sign languages end up being bilingual, in the sign language and the surrounding spoken language, or at least in its written form.”
This bilingualism contributes to the stereotype that signed languages are based on spoken languages.
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Language 101: Language Change
Language 201: Glottochronology and Dating the Evolution of Language
Language 201: Place-Names
Human Origins: Signed Languages
A Very Short Introduction to Descriptive Linguistics
A Very Short History of the English Language
Language 101: "Body Language"