American Sign Language
and the
Development of the Young Child
I. American Sign Language and Hearing Children
If you watch adults and children talk to one another, you might notice their hands moving—waving hello or goodbye, pointing to a desired object, putting a finger to pursed lips to indicate “quiet”, or rubbing a tummy to show content after eating good food. It’s no coincidence that we gesticulate more around young children. With limited language skills, children benefit from an added element of communication. If a request like “get your backpack” doesn’t register, we might try pointing to the backpack and possibly gesturing backpack straps with our hands. These added motions take the uni sensory experience of hearing speech into the multi sensory experience of connecting the spoken word “backpack” with the visual of a person pointing to said object. As we know, connections are the building blocks of learning, and utilizing multiple parts of the brain is more likely to make a concept stick.
This multi sensory approach to language development is just one among many reasons for the growing practice of using American Sign Language with young hearing children. As a physical/visual language, ASL enhances the experience of young language learners, many of whom connect better to sensations beyond the spoken form of English. Aside from its multi sensory benefits, regular exposure to ASL has also been shown to enhance the English vocabularies of young children, and speed up the rate of language development overall (Bingham, 2013; Daniels, 1994; Holmes & Holmes, 1980). Many teachers incorporate ASL not only for its developmental benefits, but also for its ability to enhance communication around needs within the classroom (Mason, personal communication, November 29th, 2017; Marshall, personal communication, October, 2017). In the following pages, I’ll analyze the existing research on ASL as it relates to language development, and offer some insight for educators and parents into using ASL as a learning tool for young children.
This multi sensory approach to language development is just one among many reasons for the growing practice of using American Sign Language with young hearing children. As a physical/visual language, ASL enhances the experience of young language learners, many of whom connect better to sensations beyond the spoken form of English. Aside from its multi sensory benefits, regular exposure to ASL has also been shown to enhance the English vocabularies of young children, and speed up the rate of language development overall (Bingham, 2013; Daniels, 1994; Holmes & Holmes, 1980). Many teachers incorporate ASL not only for its developmental benefits, but also for its ability to enhance communication around needs within the classroom (Mason, personal communication, November 29th, 2017; Marshall, personal communication, October, 2017). In the following pages, I’ll analyze the existing research on ASL as it relates to language development, and offer some insight for educators and parents into using ASL as a learning tool for young children.
II. Who uses American Sign Language?
As the various benefits of American Sign Language for hearing children come to light, it’s important to remember its original purpose as a central mode of communication for the deaf. Many hearing people assume that ASL is simply a mimed version of spoken English. In fact, it is a completely separate language with its own syntax and history. In addition to the well known hand gestures, the language utilizes facial expressions such as raised eyebrows to indicate a question, much like the upward inflection used in spoken English. Also like spoken language, sign languages vary from country to country. The version used in the US, American Sign Language, is thought to have originated from Langue des Signes Francaise (French Sign Language). ASL expression varies by region, with accents that mirror those we find in English (NIDCD, 2014).
Beyond its use as a communication system for the deaf and hearing impaired, a growing body of research has shown ASL to be a powerful tool for people with ASD, Down Syndrome, and other developmental diagnoses that impact communication. As Dr. Stephen M. Edelson writes, “Many aberrant behaviors associated with autism and other developmental disabilities…are often attributed to an inability to communicate to others” (Edelson, 2017). Specialists have found that ASL can work to bridge that communication gap, allowing nonverbal people and those with speech delays to express wants and needs through sign. When used by caregivers and educators in this context, ASL is often combined with English, a practice known as “signed speech” (Edelson, 2017). In part due to the clear benefits of using ASL as an intervention for those with speech delays, people are increasingly waking up to the idea of using ASL with another mostly nonverbal population: very young children.
Beyond its use as a communication system for the deaf and hearing impaired, a growing body of research has shown ASL to be a powerful tool for people with ASD, Down Syndrome, and other developmental diagnoses that impact communication. As Dr. Stephen M. Edelson writes, “Many aberrant behaviors associated with autism and other developmental disabilities…are often attributed to an inability to communicate to others” (Edelson, 2017). Specialists have found that ASL can work to bridge that communication gap, allowing nonverbal people and those with speech delays to express wants and needs through sign. When used by caregivers and educators in this context, ASL is often combined with English, a practice known as “signed speech” (Edelson, 2017). In part due to the clear benefits of using ASL as an intervention for those with speech delays, people are increasingly waking up to the idea of using ASL with another mostly nonverbal population: very young children.
III. Baby Signing: the Research
In the 2004 Blockbuster hit “Meet the Fockers”, Ben Stiller’s character, after witnessing a baby using ASL, reports “I’ve heard about this baby signing stuff, this is like cutting edge” (Rosenthal & Roach, 2004). While using ASL with children has certainly grown in popularity over the last decade, research on its benefits dates back far before it was deemed trendy enough to put in a major movie. As early as 1867, linguist William Dwight Whitney observed something remarkable about the children of deaf parents: These children, seen by society as naturally disadvantaged, were speaking just as early as the children of hearing parents. What’s more, they were communicating through sign language at a much earlier rate than their non-signing counterparts could communicate through speech (Bingham, 2007). Whitney’s research opened the first window into the notion that ASL might actually stimulate, not hinder, a baby’s language development, yet these contributions stayed mostly within the realm of “curious linguist”. It would be over a century before researchers brought the subject into a more academic light.
Dr. Joseph Garcia’s career started in the field of animal communication. Using gestural language with primates, he soon became interested in the potential for this type of language between humans. He began studying American Sign Language around 1975 and became a father a decade later, which helped deepen his interest in ASL as it relates to early language development. During this time, he noticed something reminiscent of Whitney’s earlier observations: the children of his deaf friends were communicating through sign as young as six months old. These findings culminated in his 1986 graduate thesis, which formed the basis for later publications on the subject. Considered one of the pioneers of “baby sign language”, Garcia’s work continues to this day in the form of “Sign2Me”, a company dedicated to all things baby sign. His extensive offering of DVDs, phonics tapes, and baby signing classes, solidifies Garcia’s journey from researcher to lucrative entrepreneur (Garcia, 2016).
Around the time that Garcia was working on his thesis, other researchers were finding similar results on the beneficial impact of ASL on young learners. Holmes and Holmes (1980) followed a child whose parents were hearing but very active within the deaf community. From birth, they used both ASL and spoken English to communicate with him, even fingerspelling the O’s in “oooooh” when cooing to him. The child acquired his first ten words a full three months earlier than his speaking-only peers. Of these ten words, six were spoken, three were signed, and one was used as a spoken/signed combination. Prinz and Prinz (1981) found similar results in their study of the hearing daughter of deaf parents, who began signing at 7 months old. Research team DeVivieros and McLaughlin (1982) showed an increase in adjectives and adverb usage among kindergarten boys exposed to ASL, and Marilyn Daniels (1993) used the famous Peabody Picture Vocabulary Test to show that hearing children of deaf parents had a higher vocabulary than children of hearing parents.
Dr. Joseph Garcia’s career started in the field of animal communication. Using gestural language with primates, he soon became interested in the potential for this type of language between humans. He began studying American Sign Language around 1975 and became a father a decade later, which helped deepen his interest in ASL as it relates to early language development. During this time, he noticed something reminiscent of Whitney’s earlier observations: the children of his deaf friends were communicating through sign as young as six months old. These findings culminated in his 1986 graduate thesis, which formed the basis for later publications on the subject. Considered one of the pioneers of “baby sign language”, Garcia’s work continues to this day in the form of “Sign2Me”, a company dedicated to all things baby sign. His extensive offering of DVDs, phonics tapes, and baby signing classes, solidifies Garcia’s journey from researcher to lucrative entrepreneur (Garcia, 2016).
Around the time that Garcia was working on his thesis, other researchers were finding similar results on the beneficial impact of ASL on young learners. Holmes and Holmes (1980) followed a child whose parents were hearing but very active within the deaf community. From birth, they used both ASL and spoken English to communicate with him, even fingerspelling the O’s in “oooooh” when cooing to him. The child acquired his first ten words a full three months earlier than his speaking-only peers. Of these ten words, six were spoken, three were signed, and one was used as a spoken/signed combination. Prinz and Prinz (1981) found similar results in their study of the hearing daughter of deaf parents, who began signing at 7 months old. Research team DeVivieros and McLaughlin (1982) showed an increase in adjectives and adverb usage among kindergarten boys exposed to ASL, and Marilyn Daniels (1993) used the famous Peabody Picture Vocabulary Test to show that hearing children of deaf parents had a higher vocabulary than children of hearing parents.
IV. Analysis
Taken as a whole, this impressive research has shown that children exposed to ASL experience many specific benefits. Among the most impressive findings are communication at an earlier age (Garcia, 2016; Holmes and Holmes, 1980; Prinz and Prinz, 1981, etc.), increased vocabulary (Daniels, 1994; DeVivieros and McLaughlin 1982) and even reportedly higher IQ levels in children exposed to ASL (Acredolo and Goodwyn, 2000). This research has formed the basis for our growing understanding that early exposure to ASL indeed improves language development overall. It also leads one to wonder how and why children are able to communicate through sign at such a young age.
The celebrated child psychologist Jean Piaget once remarked, “gesture and mime—language in movement—is the real social language of the child” (Piaget, 1955). On a physical level, babies are capable of using their hands before their voices (Fisher, personal communication, 2017). Babies who’ve been signed to will show the equivalent of spoken “babbling” by waving their hands in increasingly organized patterns before a recognizable signed word emerges. Between four to six weeks, the thumb and index fingers are the only digits capable of independent movement, making associated signs some of the first that babies are typically able to recreate (Holmes & Holmes, 1980). This of course leads one to wonder if it’s purely a physical barrier preventing babies from communicating earlier than we typically observe.
Sara Bingham, in her seminal work “The Baby Signing Book”, suggests that the answer can be found in a combination of fine motor and brain development. She defines ASL as communication through hands, while speech is a function of our mouths. Both of these, she argues, tie back to language itself, which is primarily a function of our brains.
Because the part of the brain responsible for interpreting visual stimuli develops earlier than the area responsible for analyzing auditory input, young babies get more out of your interactions when you sign and speak to them than they do from speech alone (Bingham, 2007, p. 38). It’s as if the brain is able to get “more bang for its buck”, when it processes the two languages together. Furthermore, a baby’s cerebral cortex, responsible for cognitive and motor functions, triples in thickness during the first year of life, making this a crucial time for learning language. The combined inputs of ASL and spoken language deepen a child’s metalinguistic knowledge, which Robert Siegler defines as “an understanding of the properties and function of language—that is, an understanding of language as language” (Siegler, 2003, p. 218).
In many ways, Michelle Goodwin embodies this multi sensory understanding of language. Raised by two deaf parents, her primary language is American Sign Language. She recalls her grandmother, who’s hearing, recording herself on cassette tapes that she sent to Michelle and her siblings as a way of exposing them to more spoken English. Between these tapes and her later experience in school, Michelle’s speaking ability developed much like that of her peers, yet ASL remained the primary language at home. Reflecting on it as an adult, Michelle sees this bilingualism as a serious benefit, the effects of which have stayed with her throughout her life. “I’ve always associated words with physical movement”, she says. “I remember taking this spelling test, and as I was writing the word, I was fingerspelling it under the table to help me remember. I thought I was cheating” (Goodwin, personal communication, November 28th, 2017). Clearly that feeling that she was somehow involved in foul play speaks very highly of her physical associations with language, not to mention her moral character! Much like the research by Garcia and others, Michelle came to see her multi sensory understanding of language as a true advantage in the ability to learn and retain words.
The celebrated child psychologist Jean Piaget once remarked, “gesture and mime—language in movement—is the real social language of the child” (Piaget, 1955). On a physical level, babies are capable of using their hands before their voices (Fisher, personal communication, 2017). Babies who’ve been signed to will show the equivalent of spoken “babbling” by waving their hands in increasingly organized patterns before a recognizable signed word emerges. Between four to six weeks, the thumb and index fingers are the only digits capable of independent movement, making associated signs some of the first that babies are typically able to recreate (Holmes & Holmes, 1980). This of course leads one to wonder if it’s purely a physical barrier preventing babies from communicating earlier than we typically observe.
Sara Bingham, in her seminal work “The Baby Signing Book”, suggests that the answer can be found in a combination of fine motor and brain development. She defines ASL as communication through hands, while speech is a function of our mouths. Both of these, she argues, tie back to language itself, which is primarily a function of our brains.
Because the part of the brain responsible for interpreting visual stimuli develops earlier than the area responsible for analyzing auditory input, young babies get more out of your interactions when you sign and speak to them than they do from speech alone (Bingham, 2007, p. 38). It’s as if the brain is able to get “more bang for its buck”, when it processes the two languages together. Furthermore, a baby’s cerebral cortex, responsible for cognitive and motor functions, triples in thickness during the first year of life, making this a crucial time for learning language. The combined inputs of ASL and spoken language deepen a child’s metalinguistic knowledge, which Robert Siegler defines as “an understanding of the properties and function of language—that is, an understanding of language as language” (Siegler, 2003, p. 218).
In many ways, Michelle Goodwin embodies this multi sensory understanding of language. Raised by two deaf parents, her primary language is American Sign Language. She recalls her grandmother, who’s hearing, recording herself on cassette tapes that she sent to Michelle and her siblings as a way of exposing them to more spoken English. Between these tapes and her later experience in school, Michelle’s speaking ability developed much like that of her peers, yet ASL remained the primary language at home. Reflecting on it as an adult, Michelle sees this bilingualism as a serious benefit, the effects of which have stayed with her throughout her life. “I’ve always associated words with physical movement”, she says. “I remember taking this spelling test, and as I was writing the word, I was fingerspelling it under the table to help me remember. I thought I was cheating” (Goodwin, personal communication, November 28th, 2017). Clearly that feeling that she was somehow involved in foul play speaks very highly of her physical associations with language, not to mention her moral character! Much like the research by Garcia and others, Michelle came to see her multi sensory understanding of language as a true advantage in the ability to learn and retain words.
V. ASL in the Classroom
Throughout my career as an educator, I've had a chance to see many classrooms in action. One thing that caught my attention was the prevalence of hand signals used within many of these classrooms. Like many trends in education, these hand signals were not something I remember from my own elementary school experience, so I was curious as to why and how they were being used. After further discussions with several teachers and spending more of my own time interacting in these spaces, I realized these signals were not unique to each classroom, but borrowed from the existing body of ASL signs. In all cases, these signs were being used with hearing children, across a number of grades, but primarily within preschool and younger elementary classrooms.
While the benefits of introducing ASL to babies has been well-documented (Prinz & Prinz, 1981; Garcia, 2016, etc.), I wondered if the same benefits were possible for school-aged children within the classroom. Marilyn Daniels (1994) conducted one study in a PreK program that indeed confirmed the benefits of ASL on language development, a key finding we’ve seen within research on ASL and babies. Daniels studied four PreK classrooms at the same Title 1 school. All four classes used identical curricula, but two of the classes additionally incorporated ASL. Within the ASL classrooms, signs were used to emphasize important words such as new vocabulary, and also to visually show a request or command such as “stop” or “line up”. Daniels observed that after several months of exposure to their teachers signing, children would begin to sign back, and then eventually, to sign with each other. In the spring, she administered the Peabody Picture Vocabulary Test (PPVT), which measures English vocabulary. Out of a sample size of 60 total students, those who’d been in ASL classrooms scored an average 15 points higher than their non-signing counterparts. These findings show that ASL indeed has a direct impact on children’s ability to learn language, even when their first exposure occurs at the PreK age, typically around four years old. Increasing vocabulary is a huge goal within most preK programs, and Daniels’ findings suggest that ASL could be a very effective way to achieve that.
As I spoke to other classroom teachers, I came to realize that vocabulary was just one of many beneficial impacts of incorporating ASL in the classroom. Becca Mason teaches PreK at a a charter school in Boston, to a majority African-American student body. She incorporates ASL throughout her daily routine, both as a way to communicate needs within the classroom and as a means of emphasizing academic content. “The nonverbal cues (’t’ for toilet, “help”, “water”, “me too”, to name a few), allow children to advocate for their own needs in ways that don’t stop the momentum of the learning or draw too much attention” (Mason, personal communication, November 29th, 2017). Every classroom teacher can relate to the frustration of calling on a student who seems eager to answer the question, only to hear the age-old question “can I go to the bathroom?”. Now imagine, as Becca has created, a classroom in which a student simply makes the sign for the letter “T”. The teacher sees the student signing out of the corner of her eye and, without missing a beat, can sign “yes” or “no”, while the rest of the class remains fully engaged in the lesson at hand.
In Gail Marshall’s classroom, the role of ASL is used primarily as a strategy for communicating across language barriers. Gail teaches PreK at a Philadelphia public school to students who are exclusively English language learners. They come from a variety of linguistic backgrounds, but all share the experience of speaking a home language other than English. Within this context, Gail knows that one of her primary goals in the classroom is to get students comfortable communicating both with her and with each other. She’s noticed a trend throughout the years that some students come in to her class exhibiting signs of what would be labeled “selective muteness”, though Gail suspects this is really just a product of being four, being shy, and being expected to speak a language you don’t know very well. Her response has been to encourage these students by way of ASL. Even the most vocally hesitant students show Gail the sign for “help”, thus enabling them to advocate for their needs alongside vocal peers (Marshall, personal communication, October, 2017).
Aside from the tangible benefits of increased communication, using ASL allows students to participate in a shared system that goes beyond the walls of their own classroom. While classroom teachers could have chosen to teach any random hand signal for the words and commands they wish to emphasize, the choice to use ASL specifically allows students access to other spaces in which ASL is used. That could be as simple as going to the next grade where another teacher also uses ASL, or as distant as the ability to communicate with a deaf relative via videochat. In this way, ASL can be seen to have benefits similar to any bilingual classroom: students walk away with the ability to participate in a language system beyond standard spoken English.
While the benefits of introducing ASL to babies has been well-documented (Prinz & Prinz, 1981; Garcia, 2016, etc.), I wondered if the same benefits were possible for school-aged children within the classroom. Marilyn Daniels (1994) conducted one study in a PreK program that indeed confirmed the benefits of ASL on language development, a key finding we’ve seen within research on ASL and babies. Daniels studied four PreK classrooms at the same Title 1 school. All four classes used identical curricula, but two of the classes additionally incorporated ASL. Within the ASL classrooms, signs were used to emphasize important words such as new vocabulary, and also to visually show a request or command such as “stop” or “line up”. Daniels observed that after several months of exposure to their teachers signing, children would begin to sign back, and then eventually, to sign with each other. In the spring, she administered the Peabody Picture Vocabulary Test (PPVT), which measures English vocabulary. Out of a sample size of 60 total students, those who’d been in ASL classrooms scored an average 15 points higher than their non-signing counterparts. These findings show that ASL indeed has a direct impact on children’s ability to learn language, even when their first exposure occurs at the PreK age, typically around four years old. Increasing vocabulary is a huge goal within most preK programs, and Daniels’ findings suggest that ASL could be a very effective way to achieve that.
As I spoke to other classroom teachers, I came to realize that vocabulary was just one of many beneficial impacts of incorporating ASL in the classroom. Becca Mason teaches PreK at a a charter school in Boston, to a majority African-American student body. She incorporates ASL throughout her daily routine, both as a way to communicate needs within the classroom and as a means of emphasizing academic content. “The nonverbal cues (’t’ for toilet, “help”, “water”, “me too”, to name a few), allow children to advocate for their own needs in ways that don’t stop the momentum of the learning or draw too much attention” (Mason, personal communication, November 29th, 2017). Every classroom teacher can relate to the frustration of calling on a student who seems eager to answer the question, only to hear the age-old question “can I go to the bathroom?”. Now imagine, as Becca has created, a classroom in which a student simply makes the sign for the letter “T”. The teacher sees the student signing out of the corner of her eye and, without missing a beat, can sign “yes” or “no”, while the rest of the class remains fully engaged in the lesson at hand.
In Gail Marshall’s classroom, the role of ASL is used primarily as a strategy for communicating across language barriers. Gail teaches PreK at a Philadelphia public school to students who are exclusively English language learners. They come from a variety of linguistic backgrounds, but all share the experience of speaking a home language other than English. Within this context, Gail knows that one of her primary goals in the classroom is to get students comfortable communicating both with her and with each other. She’s noticed a trend throughout the years that some students come in to her class exhibiting signs of what would be labeled “selective muteness”, though Gail suspects this is really just a product of being four, being shy, and being expected to speak a language you don’t know very well. Her response has been to encourage these students by way of ASL. Even the most vocally hesitant students show Gail the sign for “help”, thus enabling them to advocate for their needs alongside vocal peers (Marshall, personal communication, October, 2017).
Aside from the tangible benefits of increased communication, using ASL allows students to participate in a shared system that goes beyond the walls of their own classroom. While classroom teachers could have chosen to teach any random hand signal for the words and commands they wish to emphasize, the choice to use ASL specifically allows students access to other spaces in which ASL is used. That could be as simple as going to the next grade where another teacher also uses ASL, or as distant as the ability to communicate with a deaf relative via videochat. In this way, ASL can be seen to have benefits similar to any bilingual classroom: students walk away with the ability to participate in a language system beyond standard spoken English.
VI. ASL for Differentiation
A look into Gail Marshall’s classroom revealed the benefits of ASL for English Language Learners, yet these ELL students are just one of many groups that benefit from the use of ASL. As mentioned earlier, much research has been done on the benefits of ASL for students on the Autism spectrum (Edelson, 2017), as well as other learning delays. Even for students without Individual Education Plans (IEPs), ASL can provide a preferable means of communication for those that are shy or anxious within the classroom. Within academic content, some students are better able to process and retain information if they encounter a concept through multiple sensory inputs. When Becca Mason reviews colors, letters, or numbers with her PreK students, they sign along to help emphasize the words (Mason, personal communication, November 29th, 2017).
With the growing trend towards inclusion classrooms, one of the biggest challenges facing teachers is learning how to properly differentiate instruction for a range of learners. Often, IEPs contain specific accommodations that teachers must follow: ADD students may be entitled to extra time on a test, while ASD students may need instructions read aloud several times. Part of the challenge for many teachers becomes adhering to IEPs while also making sure not to call too much attention to the various accommodations different students receive. One solution is to incorporate certain accommodations into the culture of the entire classroom, and ASL lends itself well to this idea. Even if certain students (ELLs, ASD students, etc.) may benefit more directly from ASL, this fact becomes less pronounced when the entire class participates. If everyone uses ASL, no one student is singled out, and all students can assist in making the learning more accessible for everyone.
With the growing trend towards inclusion classrooms, one of the biggest challenges facing teachers is learning how to properly differentiate instruction for a range of learners. Often, IEPs contain specific accommodations that teachers must follow: ADD students may be entitled to extra time on a test, while ASD students may need instructions read aloud several times. Part of the challenge for many teachers becomes adhering to IEPs while also making sure not to call too much attention to the various accommodations different students receive. One solution is to incorporate certain accommodations into the culture of the entire classroom, and ASL lends itself well to this idea. Even if certain students (ELLs, ASD students, etc.) may benefit more directly from ASL, this fact becomes less pronounced when the entire class participates. If everyone uses ASL, no one student is singled out, and all students can assist in making the learning more accessible for everyone.
VII. ASL for All
American Sign Language will continue to be used primarily for its original purpose as the language of the deaf and hard of hearing, yet the body of research detailing its benefits for hearing children has become too powerful to ignore. ASL can be incorporated into many stages of life—from birth, as a way to promote early language ability, or in the early childhood classroom, as a way to build community and reach a multitude of learning types. Perhaps the most striking thing throughout this research is that no known downsides have been reported as a result of using ASL with hearing children. To the contrary, benefits range from the cognitive realm with increased vocabulary, to the emotional realm with the ability to express wants and needs at a young age. The language can be used to enhance the experience of parents and children within the home, as well as teachers and students within the classroom. With such wide-ranging benefits, it seems that truly everyone has something to gain from American Sign Language.
References
(No Author Listed). American Sign Language. (2017, May 19). Retrieved December 09, 2017, from https://www.nidcd.nih.gov/health/american-sign-language
Acredolo, L. P., & Goodwyn, S.W. (July 2000). The long-term impact of symbolic gesturing during infancy on IQ at age 8. Paper presented at the meetings of the International Society for Infant Studies, Brighton, UK.
Bingham, S. (2007). The Baby Signing book: includes 450 ASL signs for babies & toddlers. Toronto: R. Rose
Daniels, M. (1994). The Effect of Sign Language on Hearing Children's Language Development. Communication Education, 43(4), 291-298. Retrieved November 20, 2017
deViveiros, C. E. & McLaughlin, T. F. (1982). Effects of Manual Sign Use on the Expressive Language of Four Hearing Kindergarten Children. Sign Language Studies 35(1), 169-177. Gallaudet University Press. Retrieved December 9, 2017, from Project MUSE database.
Edelson, S. M. (n.d.). Signed Speech or Simultaneous Communication. Retrieved December 08, 2017, from https://www.autism.com/advocacy_signing
Garcia, J. (2016, July 12). Home. Retrieved December 08, 2017, from https://www.drjosephgarcia.com/home/
Holmes, K. M., & Holmes, D. W. (1980). Signed and Spoken Language Development in a Hearing Child of Hearing Parents. Sign Language Studies, 1028(1), 239-254
Piaget, J. (1955). The Language and Thought of the Child. New York: Meridian Books
Prinz, P. M. & Prinz, E. A. (1981). Acquisition of ASL and Spoken English by a Hearing Child of a Deaf Mother and a Hearing Father: Phase II, Early Combinatorial Patterns. Sign Language Studies 30(1), 78-88. Gallaudet University Press. Retrieved December 9, 2017, from Project MUSE database.
Rosenthal, J., et al (Producers), & Roach, J. (Director). (2004). Meet the Fockers [Motion picture]. United States: Tribeca Productions.
Siegler, R., Deloach, J., & Eisenberg, N. (2003). How children develop. New York: Worth .
Acredolo, L. P., & Goodwyn, S.W. (July 2000). The long-term impact of symbolic gesturing during infancy on IQ at age 8. Paper presented at the meetings of the International Society for Infant Studies, Brighton, UK.
Bingham, S. (2007). The Baby Signing book: includes 450 ASL signs for babies & toddlers. Toronto: R. Rose
Daniels, M. (1994). The Effect of Sign Language on Hearing Children's Language Development. Communication Education, 43(4), 291-298. Retrieved November 20, 2017
deViveiros, C. E. & McLaughlin, T. F. (1982). Effects of Manual Sign Use on the Expressive Language of Four Hearing Kindergarten Children. Sign Language Studies 35(1), 169-177. Gallaudet University Press. Retrieved December 9, 2017, from Project MUSE database.
Edelson, S. M. (n.d.). Signed Speech or Simultaneous Communication. Retrieved December 08, 2017, from https://www.autism.com/advocacy_signing
Garcia, J. (2016, July 12). Home. Retrieved December 08, 2017, from https://www.drjosephgarcia.com/home/
Holmes, K. M., & Holmes, D. W. (1980). Signed and Spoken Language Development in a Hearing Child of Hearing Parents. Sign Language Studies, 1028(1), 239-254
Piaget, J. (1955). The Language and Thought of the Child. New York: Meridian Books
Prinz, P. M. & Prinz, E. A. (1981). Acquisition of ASL and Spoken English by a Hearing Child of a Deaf Mother and a Hearing Father: Phase II, Early Combinatorial Patterns. Sign Language Studies 30(1), 78-88. Gallaudet University Press. Retrieved December 9, 2017, from Project MUSE database.
Rosenthal, J., et al (Producers), & Roach, J. (Director). (2004). Meet the Fockers [Motion picture]. United States: Tribeca Productions.
Siegler, R., Deloach, J., & Eisenberg, N. (2003). How children develop. New York: Worth .