The International Dyslexic Association states that one in ten individuals is dyslexic. From my teaching experience, I would estimate that closer to one-third of individuals have a dyslexic learning profile and benefit from teaching routes that ameliorate dyslexic traits. The markers of a dyslexic profile vary in intensity and degree, yet, from the non-reading adult to the non-writing teen, with appropriate instruction, all can make progress and usually, several grade levels of progress, in academic skills in ten to twenty hours of individualized, one-on-one instruction.
Over and over, I have witnessed students, from seven years of age to seventy-seven years of age, decrease directional confusion and dramatically increase the automatic and accurate processing of two-dimensional symbols through a combination of multi-sensory direct instruction methods in symbol stabilization. Many times, students note decreased reading fatigue and improved decoding in six to eight hours. Creating more accurate and automatic memories for letters in turn, improves the ease of not only reading, but also writing, spelling, keyboarding, copying from the board, etc.
Additionally, dyslexic profiles include a delay in one or more features of the language system---delays not just in phonological processing, but also in one or more aspects of receptive and/or expressive vocabulary and/or grammar. Complicated? Can be. The more areas of delay, the more profound the difficulties in reading/writing/speaking/listening. Yet, a large percentage of dyslexic learners make incredible progress with just several hours of atypical, direct language instruction in vocabulary and/or grammar. Combined with multi-sensory activities, such as building and transposing sentences with 3-dimensional pieces---which improve reading comprehension and writing structure, cognitive strategy training develops the skill of using one's own language to guide thinking, organize oneself in time and space, and complete tasks.
While the majority of people who struggle to read or write efficiently dramatically improve their skills in ten or twelve hours of instruction, the same strategies work with those who have more severe forms of dyslexia. So, for instance, I have worked with students with broad-based motor and language delays, who may require a year of instruction, but make several years of progress which enables them to "catch up" or surpass their expected grade level.
While assessing, designing, and delivering direct instruction requires training, the methods are basically simple. With careful observation, instruction does not have to be "drill and kill." We can expect all our students to succeed, and meet or surpass grade level expectations. If they do not, we are not doing our job!