According to the NIH (National Institutes of Health) research, the core issue in dyslexia is difficulty processing phonological information. The degree of difficulty varies from person to person.
Samantha, who is in 4th grade, reads “stop” for “spot”. If you ask her what letters she sees, she’ll tell you she sees “s.p.o.t” and it says “stop”. She can’t tell with her own auditory processing that she has things in the wrong order. That’s a pretty severe problem processing phonemic information.
Max, a 7th grader, would neve have made that kind of error. He hears words like “jaunty” and knows exactly what they mean. He can’t, however, tell you that there’s an “n” sound in the middle of this word. So he would spell the word “jotty”.
Both of these children are dyslexic. But Samantha’s problem is on the more severe end of the processing continuum.
Jennifer is in 1st grade. She wrote a story about all the things in the “frijooadr”: “broklee, karits, and lettus for a salid.” Jennifer is not dyslexic at all. She processes speech sounds in spoken words extremely well and will likely develop memory for correctly spelling broccoli, carrots, and lettuce quite easily.