Over two million children in the U.S. have hearing loss in one ear, and over a million have hearing loss in both ears. Tens of millions of children across the globe are hard of hearing. Most children with severe hearing loss struggle with learning how to read. Often times, they do not read better than the elementary school level upon high school graduation. However, many children who are deaf or hard of hearing are great readers. What accounts for the tremendous differences in reading skill?
There is emerging agreement that successful reading in children who are deaf or hard of hearing depends on different brain mechanisms for those who communicate predominantly in signed language versus those who communicate predominantly in oral language. This new research informs us about the nature of brain function in those with different language experience and about the brain mechanisms for learning to read in all of us. It also has direct implications for improving literacy education for children who are deaf or hard of hearing.
Factors predicting early reading success in typically hearing children
One of the strongest predictors of early reading success is phonological awareness of spoken language, which is the ability to identify and manipulate speech sounds. For example, try to say the word ‘tiger’ without the ‘g’, the correct answer is ‘tire’. Children’s understanding of the alphabetic principle is another critical predictor of early reading success. The alphabetic principle is knowing how a letter, such as ‘f’ or letter combination, such as ‘ph’, is translated to a speech sound.
As children grow older, they are expected to understand increasingly complex text; so, vocabulary also becomes an important predictor of reading skill.
Mechanisms for reading in hard of hearing children with oral communication
Children who are hard of hearing often use oral communication, especially those with mild to moderate hearing loss. These children can obtain phonological awareness of language, whether spoken or heard, to facilitate reading acquisition. Children who are deaf may have little or no access to sound, which limits their ability to use phonological awareness of spoken language for successful reading.
Lip reading also can contribute to the phonological awareness skills in children who are hard of hearing. However, much of the information necessary for recognizing spoken words is not present on the lips. Even though lip reading only provides partial information, children who are hard of hearing that are better lip readers tend to have higher reading skill.
Learning to read in deaf or hard of hearing children with signed language
Learning to read for children who are deaf and communicate with signed language presents a unique situation. Imagine having to learn to read in Thai without knowing the pronunciation, for example, that the word ‘มม้า’ refers to the written word ‘horse’. This is similar to what children who communicate with signed language need to do when learning to read. They must learn how to read without knowing the pronunciation of words. They, for example, need to learn that a certain sign refers to the written word ‘horse’ (see Figure 1). Better readers automatically activate signed language when reading, suggesting that access to words in signed language facilitates reading acquisition.
In children who use signed language, fingerspelling also helps to develop written word forms. Fingerspelling is a method to represent the letters of the alphabet with the hands (see Figure 1).
Signed language has features smaller than the word, like handshape, movement or location. For example, ‘mom’ and ‘dad’ in American Sign Language (ASL) share handshape and movement, but they differ in location (see Figure 2). Learning signed language develops sensitivity to these linguistic features, and some have termed this signed language phonological awareness.
Signed language features are somewhat analogous to the phonological units in spoken words referred to as phonemes. Phonemes are the distinct units of sound that distinguish one word from another, like ‘cat’versus ‘hat’.The sensitivity to smaller features in signed language may be used to help learning to read which requires mapping of small features in the written word, like letters, to their sounds.
Mechanisms for reading depend on communication mode
For children who are hard of hearing that predominantly use oral communication, we suggest that skilled reading relies on phonological awareness of spoken language in a roughly similar way to hearing children. This phonological awareness can be developed through residual hearing, articulation, and lip reading.
For children who predominantly use signed language, we suggest that skilled reading relies on the effective mapping of written word forms to vocabulary developed through signed language. More experience with signed language strengthens knowledge of word meanings. Written words can then be mapped to these word meanings more effectively.
“For those that do not have access to sound in their first months of life, caregivers should provide structured language input in the form of signed language.”
Recent neuroimaging research in adults supports our argument that those who predominantly use signed language engage different brain regions during reading as compared to those who predominantly use oral language. Moreover, we have shown that those who predominantly use signed language rely on regions for reading in the right hemisphere associated with signed language. Although we do not know whether the same is true for children, we have begun research into the brain mechanisms underlying skilled reading in children who are deaf or hard of hearing.
It is incredibly important for all children to have rich linguistic input from birth. Children with better language, whether oral or signed, have an easier time learning to read because reading is a way of visually representing language. For those that do not have access to sound in their first months of life, caregivers should provide structured language input in the form of signed language. This is an especially pressing issue given that 95% of deaf or hard of hearing children are born to hearing parents.
“We should tailor literacy instruction in children who are deaf or hard of hearing depending on communication mode.”
Currently, there is limited behavioral research on effective literacy education for children who are deaf or hard of hearing. Thus, definitive work in this area is sorely needed. Our new approach suggests that we should tailor literacy instruction in children who are deaf or hard of hearing depending on communication mode. Children who predominantly use oral communication should be taught how to read similar to hearing children, whereas for children who predominantly use signed language, beginning reading instruction should focus on the signed translations of the written words.
The author would like to thank Dr. David Quinto-Pozos at The University of Texas at Austin, Dr. C. Melanie Schuele at Vanderbilt University and Dr. Angela T. Scruggs, Nationally Certified Interpreter and Qualified Mental Health Interpreter, for their comments on this blog post. This post is a collaboration with BOLD – Blog on Learning and Development.