The symptoms of dyslexia are well known. Children with the disorder have trouble learning to read. They may also have problems with hearing the individual sounds in words and understanding how those sounds go together to make a word. They have a tendency to confuse certain letters, such as "b" and "d."

Often a person with dyslexia has a problem translating language into thought, as one does when listening and reading; or translating thought into language, as in writing and speaking.

Common symptoms of dyslexia include problems with:

• Identifying single words
• Understanding sounds in words, sound order, or rhymes
• Spelling
• Transposing (reversing) letters in words
• Handwriting
• Reading comprehension (understanding)
• Delayed spoken language
• Confusion with directions or handedness (right-versus left-handedness)
• Confusion with certain concepts, such as "up" and "down," "early" and "late," and so on
• Mathematics