Final answer:
Marshall most likely suffers from dyslexia, which makes reading and spelling difficult due to problems with sound-letter matching, and dysgraphia, making handwriting challenging and often illegible.
Step-by-step explanation:
Marshall likely suffers from dyslexia and/or dysgraphia. Individuals with dyslexia have difficulties with sound-letter correspondence, leading to a disordered way that the brain processes letters and sounds, which makes learning to read and spell words correctly very challenging. This neurological condition can cause individuals to mix up letters within words (letter reversals) and skip entire words when reading or writing.
Children with dysgraphia experience difficulty with the physical task of writing. Despite having a typical IQ, writing legibly is a struggle, and they may find it exceedingly challenging to put their thoughts on paper. This difficulty is disproportionate to their intelligence and other abilities. Moreover, children with dysgraphia require academic accommodations to aid their success in school, such as the option to take oral exams.