Why Alternative and Augmentative Communication Helps Verbal Language Development
By Daniel Miller, MA, MS, CCC-SLP
Some children (and adults) with speech and language disorders do not produce verbal language on their own, and require assistance to develop functional communication skills. Speech-language pathologists (SLPs) can help these individuals and their families select an appropriate AAC modality to best suit that person’s needs. “AAC” stands for “Augmentative and Alternative Communication.” This can come in many forms, including “no-tech” AAC, which usually takes the form of gesture and sign language, “low-tech” AAC such as a picture exchange to communicate desires and visual schedules to help with transitions and expectations, and “high-tech” AAC, which includes electronic devices which can produce speech at the press of a few buttons.
AAC is intended to open up a path to functional communication skills for individuals who do not produce verbal language, or whose verbal language is limited or very difficult to understand. AAC can be a supplement to existing verbal communication (“augmentative communication”) or it can fill the role of verbal communication for children and adults who do not produce any (“alternative communication”).
But there is a persistent concern among families who learn about AAC as an option, particularly for the families of young children who are not yet speaking. Will using AAC give the child an “easy” option, so that they never need to learn to speak? Will using AAC cause a child to stop using any speech that they may already use, or prevent them from learning more? The answer to these questions is, simply, no – in fact, there is evidence that use of AAC actually supports the further development of verbal language skills.
In 2006 Millar, Light, & Schlosser published a meta-analysis of the available research into AAC and speech development. A “meta-analysis” is a study which systematically reviews a number of studies, typically performing a statistical analysis to determine whether a particular effect is significant across multiple studies. The meta-analysis authors found that, while many of the available studies had flaws in their experimental designs (such as lack of a control group), there were a small number of studies which provided high-quality empirical evidence regarding AAC and verbal language development. Studies investigated individuals with a number of different developmental disabilities which typically have an associated speech-language disorder, including Autism, Down Syndrome, and unspecified global developmental delays.
Their conclusions? Best evidence showed that all but 1 of the 17 individuals (adults and children) who participated in intervention with AAC showed gains in their verbal communication as well. There was never a negative impact, and the one participant who did not show gains in verbal communication was a 36 year old male who simply showed no change – all of the children involved in intervention with AAC demonstrated gains in verbal language.
There are two theories behind these gains. One is that use of AAC bypasses the cognitive and speech-motor challenges that some individuals have in producing verbal language. This allows the individual to more rapidly acquire the “idea” behind communication, and to begin communicating functionally. Once these skills begin to take shape, verbal language development will follow. Verbal language is faster and more efficient than AAC, and individuals will learn and use the fastest and most efficient means of communication available to them.
The second theory is that using AAC reduces the pressure placed on an individual to communicate verbally. This may indirectly facilitate verbal language development, as learning can be hindered by communicative pressures. In fact, even without AAC, when working with young children age 2-3 who are not yet speaking, one of the first intervention strategies is to modify the child’s communication environment and the way in which caregivers interact verbally with the child. This includes a decrease in the number of questions we ask and an increase in comments (so: “I see a carrot!” instead of “What’s this?”). Why? Because decreased communicative pressure is known to lead to an increase in communication.
Hopefully this article has provided some insight into the advantages of AAC and has helped to dispel myths surrounding it. AAC does not prevent or replace verbal language development in children who have that capability, and in fact quite the contrary: AAC has been shown to facilitate verbal language development. Millar, Light, & Schlosser conclude that AAC should not be treated as an “either-or” intervention strategy, and should not be a last resort. For nonverbal children or children with limited verbal output, AAC is a valuable intervention tool for speeding the development of functional communication and verbal language.
Millar, D., Light, J., & Schlosser, R. (2006). The impact of augmentative and alternative communication intervention on the speech production of individuals with developmental disabilities: A research review. Journal of Speech, Language, and Hearing Research, 49, 248-264.