While poor spelling is a hallmark of dyslexia, it occurs in other students as well. This excellent article should help parents and teachers understand how to teach spelling beyond the "write it 5 times" mantra.
Reading Rockets: Spelling and Dyslexia.
Reading Rockets: Spelling and Dyslexia.
What are the implications for teaching? Spelling instruction that explores word structure, word origin, and word meaning is the most effective, even though students with dyslexia may still struggle with word recall. Emphasizing memorization by asking students to close their eyes and imagine the words, or asking them to write words multiple times until they "stick" are only useful after students are helped to understand why a word is spelled the way it is. Students who have learned the connections between speech sounds and written symbols, who perceive the recurring letter patterns in English syllables, and who know about meaningful word parts are better at remembering whole words. Classroom spelling programs should be organized to teach a progression of regular spelling patterns. After first grade, spelling instruction should follow and complement decoding instruction for reading. Children should be able to read the words in their spelling lesson; most learners can read many more words than they can spell.
Understanding correspondences between sounds and letters comes first. For example, before spelling a word, students can orally take the sounds of the word apart. Then, they can recall the letters that spell those sounds. Next, patterns such as the six basic syllable types of English should be taught because they represent vowel sounds in predictable ways. Third, students should be taught a few basic rules for adding endings to words, such as when letters should be doubled, when y is changed to i, and when the silent e is dropped.