Review of Studies Related to Sign Language and use of AAC in Early Intervention

Written by Amanda Franklin

Amongst five studies I compiled for review, there are a few things to compare; use of augmentative and alternative communication (AAC) versus non-use of AAC, results from use of AAC in children that are neurotypical verses use of AAC in children with intellectual disabilities (ID), and the impact of social-environmental factors in children using AAC. These factors are some of the most integral parts of these studies and contribute to the most significant outcomes.

Relationship with Hearing, Disability, and Communication

In children who learn to use AAC, they develop ways to communicate in multiple ways, by signing, gesturing, using facial expressions, eye gaze, etc., and it gives them the ability to communicate in situations where they once may not have been able to. In control groups of some studies, in which infants did not learn sign language, they scored lower than their signing trained counterparts on language outcomes, however, the differences were not statistically significant. This is seen across the board in many studies for children that are hearing and neurotypical, where there are slight differences in scores and skills, but the differences are not statistically significant and therefore show that there is no strong evidence that supports or disproves the benefits of using sign language.

There is a stark difference between the results of the studies that analyze the use of sign language in early childhood in children that are neurotypical as opposed to using sign language with children with special needs. The predominant result of studies that focus on the use of sign language in children that are neurotypical is that there is no evidence that supports the idea that the use of sign language has long-term positive benefits in cognitive and linguistic development. There is also no notable evidence that supports the idea that the use of sign language detracts from a child’s verbal language development. Contrary to the results of the studies for neurotypical children are the studies that focus on the use of sign language in children who have intellectual disabilities. In those studies, the children grow in their language development, while also improving other parts of their lives through the ability to communicate. The main difference being that in one situation the child is fully capable of developing a means of communication, whereas the child who has an ID may rely on the alternative form of communication. However, in both cases it is shown that signing does not defer verbal language development, and in some cases it allows the child to develop some verbal language skills.

Impact of Social-Environmental Characteristics

In many of the studies used for this review, social-environmental factors greatly impact the outcomes of the studies as interactions in the home and in other natural environments in which the child would typically be, with or without the presence of a disability. Interactions with the parents are mentioned most frequently, as parent’s drive to interact with their child makes the interactions meaningful or purposeful matters. It is common for parents who have a child with a speech delay to have less frequent interactions, regardless of the child’s need for an enriching language environment. The frequency of interactions and opportunities to utilize communication methods are very important to the development of language and language skills. In giving parents specific language strategies, it gives them structure, purpose, and direction with which positively affects vocabulary growth. This doesn’t show in situations where the child is neurotypical and receives the typical amount of interaction with parents because the child does not need additional support like the child who is already delayed and receiving less linguistic input. Knowledge, attitude, frequency, and ability of usage of sign language impact the parent’s interactions with their child and therefore impacts their child’s ability to learn and use language.

Limitations of the Studies

Overall, the studies call for more research into the benefits or drawbacks to the usage of sign language in young children that are hearing with hearing parents. The fact of the matter is that these studies are often too small and the data is not statistically significant. The study that is the most comprehensive shows its results in narrative form, giving context for each of its participants. Context matters in the individual cases as progress may not be as great for one child as it is for another and skew the data. With context, the child, their social-environment, and their ability levels factor into the results. For children who are neurotypical, the effects of learning baby sign as an infant has short lived effects as language development progresses, but for children who have an intellectual disability sign language can give them a method of communication that they did not have access to.


Throughout the studies there is a theme of weighing the benefits of signing verses not signing with a young child. Overall, the studies show that there are no adverse effects to using sign with a child. For children who have an intellectual disability, the studies show development in different areas for different children. There is no evidence to support the proposed theory that using sign language with young children delays spoken language. There is still a need for more studies related to the use of signing with young children who have intellectual disabilities or speech delays, and more research is needed specific to the impact of certain variables related to social-environmental factors and language development. The outcome of these studies are that there are some temporary benefits to using sign language and gesturing with young children that are neurotypical. There are also some benefits for children who have an intellectual disability or a speech delay. However, there are different levels of intervention required for each case. The use of sign is not a one-size-fits-all model and children with more severe needs will have a drastically different experience than a child with a moderate speech delay. The use of sign also really has to be something that the parents want to invest time and effort into using with their child as those interactions make an impact on whether or not the child picks up the method of communication. Regardless, children have the will to communicate needs, wants, and ideas. It comes down to the resources, ability, attitude, and circumstances of each child whether or not this is a good option for them. The studies in this review show that participants are affected in many different ways and that the frequency and purpose of interactions with children who have communication difficulties have value in the overall cognitive and linguistic development.



Brady, N. C., Thiemann-Bourque, K., Fleming, K., & Matthews, K. (2013). Predicting language outcomes for children learning augmentative and alternative communication: child and environmental factors. Journal of Speech, Language, and Hearing Research, 56(5), 1595-1612 .

Fitzpatrick, E. M., Thibert, J., Grandpierre, V., & Johnston, J. C. (2014). How handy are baby signs? a systematic review of the impact of gestural communication on typically developing, hearing infants under the age of 36 months. First Language, 34(6), 486-509.

Seal, B. C., & DePaolis, R. A. (2014). Manual activity and onset of first words in babies exposed and not exposed to baby signing. Sign Language Studies, 14(4), 444-465.

Toth, A. (2009). Bridge of signs: can sign language empower non-deaf children to triumph over their communication disabilities? American Annals of the Deaf, 154(2), 85-95.

Vandereet, J., Maes, B., Lembrechts, D., & Zink, I. (2011). Expressive vocabulary acquisition in children with intellectual disability: speech or manual signs? Journal of Intellectual & Developmental Disability, 36(2), 91-104.


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