Language is innate. Reading isn’t. That’s the hypothesis of Maryanne Wolf in Proust and the Squid:
[…] reading and other cultural inventions differ from other processes; they do not come “naturally” to children, unlike language or vision […] Across all written languages, reading development involves: a rearrangement of older structures to make new learning circuits; a capacity for specialization in working groups of neurons within these structures for representing information; and automaticity — the capacity of these neuronal groups and learning circuits to retrieve and connect this information at nearly automatic rates. (169-170)
An important piece of evidence supporting the idea that we do not possess a reading centre in the brain comes from brain scans of readers of different languages. The scans reveal that readers of English, a language with an alphabet system, activate different parts of the brain than readers of Chinese, a syllabary. The Chinese reading brain does not display any activity in the temporal-parietal region; and although both English and Chinese readers use the occipital-temporal region, the English do so using only the region of the left hemisphere, whereas Chinese readers work across both hemispheres.
So is language in the brain and reading isn’t? No. Because as we learn how to read — or learn any other skill, for that matter — the brain rewires or strengthens certain circuits, allowing us step-by-step to automatize certain processes and thus enabling us to take reading to the next level, comprehension. Language, on the other hand, is in the brain from the start. At least that’s the claim of linguists supporting the innateness hypothesis, prominent proponents of which include Noam Chomsky and Steven Pinker. The argument for language being innate draws on diverse areas of language processing and acquisition: the learning rate of language in children; language among deaf children; sophisticated language among primitive tribes; the inability of animals to acquire language; specific and inherited language disabilities.
Wolf comments on the latter area at length in her chapters on dyslexia. In a significant number of cases, dyslexia appears to be linked to regions of the brain that are crucial to language processing, such as Broca’s area or Wernicke’s area. Wolf mentions an experiment by Isabelle Libermann and Don Shankweiler whose results suggest that deaf children struggle with reading not so much because of their lack of auditory perception but because they do not have the necessary phonological representations of sounds within words. Libermann and Shankweiler concluded that when it comes to reading cognitive awareness of the sounds in a language is more important than being able to actually hear the sounds. Despite the importance of phoneme awareness (alongside the ability to decode graphemes) and the role of language regions, Wolf maintains that a failure to read can have various sources in the brain, ranging from visual to auditory to speech impediments. Her conclusion: “Voilà: the sum of these hypotheses [about the roots of dyslexia] looks like a decent approximation of the major parts of the universal reading system.” (177) A reader’s brain, in other words, functions like a computer in that it wires different sections of the brain together so as to produce the miracle we call reading.