Sign Language as a Natural Human Language


This paper is a review of linguistic literature and one study pertaining to sign language. The study under review is Dr. Laura Petitto’s work with babies, both hearing and deaf, who were at the stage of language acquisition at the time of the study. Petitto’s study went a long way in establishing sign language as a natural human language. The literature under review is “Language is not just speech” (231-262) and “Language and Communication” (15-37), the former chapter being one that lists and discusses Charles Hockett’s design features of language in Stephen Anderson’s book, Doctor Doolittle’s Delusion published in 2004.

This paper will show how Pettio’s work with babbling babies helped to establish signing as a language. This paper will briefly discuss some of Hockett’s design features and why linguists now widely and generally agree that signed human languages are able to do everything spoken human languages can. This paper will also give a brief review of Ray Jackendoff’s “American Sign Language” from Patterns in the Mind: Language and Human Nature (83 – 98) published in 1994. Furthermore, a definition of language and brief history of sign language will be included. Overall, this paper will show that sign language is a natural human language.

Babbling Babies

Human deafness has been a way for linguists to study human language. Psychologist Laura Petitto, who studied babbling in babies during the early nineties, has compiled evidence to show babies babble “not because [their ]vocal tract is maturing, but because [their] language ability is maturing.”

Interestingly, Petitto’s work with children during the early stages of language acquisition was able to show that babbling was taking place in not just hearing children but also in deaf children as well. However, the babbling was quite different in the deaf children because the deaf children were actually babbling with their hands and not their vocal tracts. This helped in proving that human language is innate and that any normal person will pick up any languages that are available to a person during this period of language acquisition or “when the language organ is growing” (Anderson 33). Language is involved in babbling, not just speech. Overall, practicing of speech is not at the physical level, but at the brain level.  Petitto’s work proves that signing is an effective medium for language. Next, a discuss of some of the harder to prove features of sign language as human language using Charles Hockett’s well known list of design features of language.

Sign language and Hockett’s properties

Most languages we study, as Anderson contends, is based on Charles Hockett’s vocal-auditory channel feature (232). However, the vocal-auditory channel is not the only way that humans use language. Indeed, human signed language uses the arms, hands and facial features in a way that is just as recursive as vocal tract speech in terms of organization such as phonemes, morphemes and syntax (Dept. of Lingusitics 431-434).

When using Hockett’s design features as a way to prove that human signing is a language, some channels are more difficult to prove than others. For instance, if one is under the impression that singed language is not recursive, then one might be hard pressed to admit that openness and productivity, which is the ability of human languages to be limitless in potential meanings (Anderson 30), is a feature of signed languages. Similarly, many people might be surprised to learn that prevarication, which is the ability of human language to talk about things that are not true or real, like Unicorns (Anderson 31), for example, is present in human signed languages as well as human spoken languages.

The ability of humans to develop language is due to language being a human organ, identical to the skin in terms of human qualities present in DNA structure. For example, just as every normal human will grow skin, every normal human will grow language. Deafness, most linguists now agree, is more than likely not going to get in the way of language acquisition.

History and definition

Signed languages, according to Anderson, can develop naturally within any community. He uses the example of what happened on Martha’s Vineyard where inbreeding led to congenital deafness to the point where so much of the population was deaf in the first half of the twentieth century that sign language was not only employed as a means of communication by hearing persons, but sometimes even used in favor of spoken speech (236-237). Furthermore, Anderson points out that sign language is different depending on geographical location just as much as any other language would be; however, he points out that American sign language, for instance, is going to be “quite independent of any substantial basis in the spoken language of the surrounding hearing community” (237).  He goes on to point out that signed languages can be just as arbitrary as spoken languages (238-239).

Ray Jackendoff points out that American Sign Language is not English. It is not a “coding of English into manual signs” (83). Much as Chinese is different from English,  Chinese Sign Language is different from Chinese spoken language, not just in terms of delivery (one using the arms, hands and face and one using the vocal tract) but also in terms of arbitrariness (another feature of Hockett).

The idea that a word can be different for a thing even though the thing stays the same is something that Anderson explains in “Language and Communication,” using the example of the word cat. The word cat is gato in Spanish so one can see that the word changes, but the cat stays the same (27), and so it is the same for sign language.

Signers do not universally act out what a cat is like a game of charades. Instead they have arbitrarily, just like any other language, assigned a sign for cat. And the sign for cat in American Sign Language is not going to be the same necessarily as the sign for cat in Chinese Sign Language.

Another example is the sign for “father” in American Sign Language which is an open right hand with the thumb touching to the forehead, whereas the sign for “father” in Chinese Sign Language is a closed right hand with the thumb touching to the lips. In comparison to what Anderson portends, in terms of sign language, is not transparently iconic, neither then is the string of letters English speakers put together to form the word “father.” In other words, Anderson is pointing out that sign language is not a game of pantomime or something made up on the spot to communicate a concept, but rather just as deliberate and yet just as subjective as any other human language.


The need to express brain activity in the form of language seems to be as important to human development as breathing oxygen, especially in terms of  Petitto’s very important work with babbling babies in the nineties that showed language will find a medium of expression one way or the other, through the vocal tract or through the hands, arms and face. Furthermore, Anderson and Jackedoff’s work goes a long way in breaking down the individual parts of human language and showing how sign language has all the parallel pieces of spoken language. Altogether, the study and the literature show why linguists agree that sign language is a natural human language.

Works cited
Anderson, Stephen. 2004. “Language is Not Just Speech”. In Doctor Doolittle’s Delusion (231-262). New Haven and London. Yale University Press.
Dept. of Linguistics, Ohio State University. 2001. “American Sign Language.” In Language Files (431-439).
Jackendoff, Ray. 1994. “American Sign Language.” Patterns in the Mind: Language and Human Nature (83-98). New York: Basic Books.
Petitto, Laura. 1991. “Babbling Babies.” Scientific American Frontiers. PBS. <;


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  1. #1 by American Sign Language Online on September 21, 2010 - 12:57 pm

    Great post. I often thought that this would be helpful to me. Thanks and keep posting!

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