Dyslexia is not a rare condition. One child out of five or one child out of ten is dyslexic, depending on where your cut-off is. Some are mildly (borderline) dyslexic; some are garden-variety; some are severely dyslexic. They can be average or below-average in intelligence, but many are extremely bright. First you have to rule out big problems like low intelligence, not knowing English, or having a mother that doesn't read to her children and talk to them. If you have ruled out these problems, the dyslexic child is the one who has more trouble than the other children with sounding out words or memorizing sight words. In other words, recognizing dyslexia in an informal way is not rocket science.
If you want to know about the dyslexic brain, Sally Shaywitz, who wrote "Overcoming Dyslexia" and does MRIs of dyslexic children, has found that dyslexic children do process letters and words differently from non-dyslexics but that they often respond well to early intervention.
Dyslexia is easier to diagnose when the child is somewhat older (partly because there are so many late bloomers), but early intervention in kindergarten or first grade really helps (as it does with speech therapy). The important thing is that we don't have to wait for the perfect diagnosis before we start to work on learning the letters. Playing games with letter-sounds (not letter-names) is an appropriate intervention for the youngest children if you use picture-letters that take the rote memorization out of the process. (See www.mnemonicpictures.com for free games that link letters with key words that have the letter-shapes built into them).
Don't ask a young beginner to sound out words if he or she can't yet put sounds together. Some children are late bloomers and may not be dyslexic after all. Spelling words with letter-cards is easier for these children than reading them. (See the packets games in my website).
Aside from having trouble memorizing which letter goes with which sound--memorizing abstract symbols by rote--dyslexics often (not always) have trouble memorizing words at sight, especially words with irregular spellings. (See my website for color-coding the vowels). Or they have trouble sounding out the letters in their correct order. (See my website for Spelling With Clues). Older dyslexics (even mildly dyslexic ones) tend to confuse look-alike words like "left" and "felt" or "head" and "hard." Reversing B and D is not the best indicator because some dyslexics don't reverse letters and some non-dyslexics do, although reversals tend to persist longer in dyslexics.
Dyslexics do better if you prepare every word for a book before they start to read it. Many beginner books are not at all systematic about building reading vocabulary. And may phonetic books introduce consonant blends (like the mp in stamp or the tr in trip) too soon in the learning sequence.
I'm offering my materials free (with manuals) through e-mail attachments. I am a grandpupil of Anna Gillingham (for those who know about Orton-Gillingham procedures), but I have been adding memory tricks, games, and color coding to the mix throughout most of my fifty years of tutoring dyslexics.
Ann Turner
www.mnemonicpictures.com