From dyslexiahelp.umich.edu

Phonological awareness affects learning to spell

Given that many dyslexics have difficulty hearing the individual sounds in our language—a skill that underlies spelling—many dyslexics have difficulty learning to spell.

The English orthography is derived from many other languages: Greek, Latin, and French to name a few. As a result, many English sounds are spelled more than one way. This makes learning to spell in English more difficult than in other alphabetic orthographies where one sound is represented by only one letter.

Yet, English spelling is rule-governed. It is estimated by some that 90% of English spellings are predictable based on spelling rules and patterns. Yes, there are exceptions to those rules, but there are rules and patterns to teach spelling.

That said, teaching spelling can be challenging. It is helpful to become familiar with morphological structures, roots, affixes, prefixes, and suffixes.

Take a look at this Wikipedia page for a great look at the complex nature of English orthography.

he first step is an assessment of spelling to determine where the breakdown is — at the syllable level, the phonemic level, or the orthorgraphis level. After establishing baseline and goals, a good next step when teaching spelling rules and combinations is to heighten your client’s awareness of his or her spelling strengths and weaknesses. Explain that through teaching he or she will gain a better insight into spelling rules, combinations, and exceptions.

Spelling instruction follows a logical progression that starts with phonemic awareness. If the error analysis demonstrates intact phonological awareness skills, skip right to teaching letter and letter combinations that represent the sounds in our language. In the English language, 44 sounds (phonemes) are represented by 26 letters (graphemes) or letter combinations. It is important to teach your client that when we spell we manipulate the word (i.e. take it apart) into its individual sounds or morphological units and then encode or transform those sounds or units into the letter or letters representing each sound or unit. There is a lot to think about when teaching spelling: syllable structure, spelling rules, homophones, silent letters, suffixes and prefixes, to name a few.

The following is a list of guidelines for teaching spelling:

• As with all therapy or teaching, sessions need to be structured, sequential, and have a logical progression from one target to the next. Lessons should be cumulative, ensuring that new information is introduced only when previously taught material has been fully absorbed.
• In the first or early treatment sessions, make sure the client has a secure understanding of sound-symbol correspondence and letter name knowledge. You may need to begin with phonological awareness tasks – taking words apart at the syllable and sound level.
• Dividing words into syllables can help students identify spelling patterns at the morphological level.
• Limit the introduction of new information to reduce confusion.
• An awareness of morphology should be incorporated into the teaching of spelling from the earliest stages.
• Teaching should encompass the integration of
  • spoken and written language
  • word, sentence, and text-level learning
  • reading and writing skills.
• Do not teach too many spelling patterns within a lesson. For example, you might decide to contrast –tion versus –sion in a lesson. This will require acute attention to the verbal production of “shun” (-tion) as in “production” versus “zhun” (-sion) as in “lesion.” And then, what do you do with “expansion” and “seizure?”

A bit about the exceptions to the rules—A person with dyslexia can be at a disadvantage, particularly when learning the exceptions, not only because of the phonological deficit that underlies the disability, but because of a lack of access to the printed word. One way we learn exceptions to spellings is by being exposed to these words when reading. Given that reading is difficult, the dyslexic will have less exposure to words through the printed form. And, they’ll have less exposure to sophisticated vocabulary.

Therefore, it behooves us to expose the dyslexic to as much sophisticated written text as possible. Text-to-speech programs are an excellent way for the dyslexic to follow along and have the text read out loud. When using books on tape, the individual should always read along with the text. This will give more exposure to spelling patterns, particularly important for learning those exceptions to the rule.

Additionally, seeing the word in print also helps one use Spellcheck. For some dyslexics with more severe spelling problems, the goal may be to become proficient enough that Spellcheck will pick up their errors. But, they still need to know which word from the choices is the one they want. Exposure to the word in print will facilitate this skill.

As noted above, we need to take a systematic approach to teaching spelling.

Although learning to spell (and teaching spelling) may be challenging, it helps to keep in mind that just as with any task (e.g., becoming a football player or learning an instrument), becoming proficient takes hard work and practice. With a systematic approach, the rules, patterns, and anomalies of English spelling can be learned. Success starts here!