Dyslexia is probably the most misunderstood learning disability. When I ask people what they think dyslexia is, they typically respond, "Reversing letters and numbers." Even psychologists at my continuing education workshops have given this response! This shows the widespread nature of this misunderstanding. When the word dyslexia, is broken apart, it means difficulty (dys) reading (lexia). So, dyslexia, is, very simply, a learning disability that affects sounding out (decoding) and reading individual words. It is based in a fundamental deficit in phonological awareness, which is the ability to take in, take apart, and put together the sounds that make up words.
Dyslexia is the only learning disability for which there is a definition-based on research, or, what is referred to in clinical practice as an evidence-based definition. This definition, established by the International Dyslexia Association, states that:
Dyslexia is a specific learning disability that is neurobiological in origin. It is characterized by difficulties with accurate and/or fluent word recognition and by poor spelling and decoding abilities. These difficulties typically result from a deficit in the phonological component of language that is often unexpected in relation to other cognitive abilities and the provision of effective classroom instruction. Secondary consequences may include problems in reading comprehension and reduced reading experience that can impede growth of vocabulary and background knowledge.
What this means is that people with dyslexia have a difficult time recognizing that words are composed of individual sounds, or phonemes. Without this skill, they cannot decode words into sounds when reading or encode sounds into words when spelling. As a result, they read individual words very slowly. That is, they are not automatic or fluent readers of individual words. Because of this, they are also are not fluent, or quick, when reading text. This is why their reading is slow and inefficient. Difficulty encoding when spelling slows their speed when writing and, because of additional problems with spoken language, discussed below individuals with dyslexia, can struggle with expressive writing, as well as with reading comprehension.
Some people with dyslexia have an additional deficit in rapid naming, which is the ability to look at and name letters, digits, colors, or pictures of objects quickly. This is a second factor that slows reading, because after a word is decoded and read, rapid naming in rapid naming slows the speed at which the meaning of the word can be accessed.
Dyslexia is, at its core, a disorder that affects language more broadly. They may have difficulty understanding what they hear, which is a deficit in comprehension of spoken language, also called receptive language. In addition to affecting the ability to understand directions or information presented in lectures, this is a third factor can affect reading speed, because it slows comprehension of what is being read. However, for most people with dyslexia, spoken language comprehension is stronger than reading comprehension. And, for some, it can be very strong. This is why audio books from digital files or CDs (e.g., Recording for the Blind and Dyslexic; Bookshare) or speech-to-text software (e.g., Kurzweil 3000) can be very helpful. Moreover, new speech-to-text features on e-readers (Kindle, iPad) make books even more accessible to individuals with dyslexia without additional assistive technology.
