Surface Dyslexia: Another Form of Context Blindness in Autism?

- Sarah Wayland Author: Donna Henderson, Psy. D Poor awareness of the sounds of language or a lack of understanding of the spelling-sound correspondence is the cause of the most common type of dyslexia. People with this type of dyslexia will make spelling errors that do not make phonetic sense (such as spelling “desk” as deks or “with” as weth). In contrast, I have noticed that some of the children I work with have an unusual pattern of spelling errors. These kids seem to understand which letters go with which sounds, but they actually over-rely on the letter-sound correlation. For example, they might spell the word “garbage” as garbij or the word “wiggle” as wigul. To understand these different types of errors, it’s important to first understand how children learn to read as well as what typical dyslexia looks like. It all starts with the phoneme. A phoneme is the smallest unit of sound, and there are 44 phonemes in the English language. In the word “cat”, for instance, there are three phonemes (/k/ – /æ/– /t/). Both speaking and reading rely on being able to identify, distinguish, blend, and manipulate these phonemes. Good readers know that specific written letters are associated with particular sounds (the phonemes) and that the sounds (and thus the letters) must be in the proper order. Beginning readers and writers must use the phonological form of the word to determine how say or spell it. However, the English writing system does not necessarily observe a one-to-one correspondence between letters and sounds.  For example, if we see the letter “k” we associate it with the /k/ sound, but if we see the letter in a certain context (knife), we know that the sequence of letters will alter the sound of that particular “k”.  Likewise, the letter “c” can be pronounced as /s/ or /k/ (as in “concise”), depending on the word’s origin and the letters that surround it. Knowing the rules that govern a letter’s pronunciation can make decoding words much easier. There are many of these irregular words, such as “laugh” and “neighbor.” These words cannot be sounded out; to read or spell them, the reader must either be able to recognize the word automatically from memory (a sight word) or know how to apply the unique reading and spelling rules. The spelling rules of English can be difficult to learn, as there can be many ways to spell the same sound. The phonological awareness skills (to sound out regular words) coupled with a knowledge of the spelling rules of English (to cope with irregular words) are both necessary for fluent reading and writing. Good spellers must know the spelling rules of English in addition to having good phonological awareness. In the most common type of dyslexia, phonological dyslexia, people do not have adequate phonological skills, so they have difficulty sounding out or spelling even regular words. Other students, however, may have adequate phonological skills but fail to fluently use [...]