I have a child who is dyslexic. There are a number of forms of this cognitive processing disorder. This individual's improves when on certain medication.
Some forms of it are treatable with medication, some do not appear to respond to any known meds.
I'm not a cognitive psychologist, but IIRC, dyslexia is an apparent temporary disconnect between the recognition of written symbols (letters, numbers, etc.) or language sounds (phonemes) and the processing order of the symbols. Thus dyslexia can be observed with written language and numbers as well as words. When the person is asked to reproduce a string of symbols or phonemes they do so out of the original order.
Some people, myself included, have what can probably described as weak or mild dyslexia. It manifests mostly when I'm stressed or not paying full time and attention to what I am typing. It is not usually treated with medication, but requires the individual to pay particular attention to handling words or strings of numbers.