I think the scientific explanation is that.... it's complicated. Higher order stuff like language & comprehension can be harder to pin down to specific areas of the brain. For example, people with stroke damage who can't speak, can often sing instead. So they are good with physical output, but the mode of output is "wrong".
Some of the parts of the brain that are involved in language and comprehension are fairly distinct and well-known. In general, the parietal lobe is responsible for spoken language ability. If there's damage or stress in the part of the frontal lobe known as "Broca's Brain", a person can understand well but have trouble speaking. If there's damage or stress in the area called "Wernicke's Brain" (located near the upper part of the temporal lobe, near the auditory cortex/ear), then a person might speak grammatically (though not necessarily relevantly), but be unable to understand the speech of others. There are definitely sub-cortical areas that are important too, but the deeper parts of the brain haven't been as well studied or mapped out.
Reading and writing are less tied to well-defined parts of the brain (because they are relatively "new" processes, evolutionarily speaking). There is a part of the brain located between Wernicke's area and the visual cortex of the occipital lobe. Abnormalities in that area are linked to some problems with reading and writing.
Then there's the whole Left-Brain Right-Brain thing. Loosely-speaking, the right brain has more to do with absorbing information, and the left brain has more to do with organizing information. (It's not always that clear-cut. Each half of the brain can do the other's work, just not as efficiently). The differences tend to show up while thinking or learning. For instance, very right brain-dominated types might be great with ideas, but poor spellers.
Since my seizures are aura-less and infrequent, it's hard to know the seizure-related problem areas. My job is a visual one, so I hope that part of the brain works well most of the time! I think input of both kinds (audio and visual) goes downhill when I'm pre-ictal, but that's just a hunch.