The Language Instinct: How the Mind Creates Language by Steven Pinker Page B

language-impaired, twelve were normal. The language-impaired children were randomly distributed among the families, the sexes, and the birth orders.
    Of course, the mere fact that some behavioral pattern runs in families does not show that it is genetic. Recipes, accents, and lullabies run in families, but they have nothing to do with DNA. In this case, though, a genetic cause is plausible. If the cause were in the environment—poor nutrition, hearing the defective speech of an impaired parent or sibling, watching too much TV, lead contamination from old pipes, whatever—then why would the syndrome capriciously strike some family members while leaving their near age-mates (in one case, a fraternal twin) alone? In fact, the geneticists working with Gopnik noted that the pedigree suggests a trait controlled by a single dominant gene, just like pink flowers on Gregor Mendel’s pea plants.
    What does this hypothetical gene do? It does not seem to impair overall intelligence; most of the afflicted family members score in the normal range in the nonverbal parts of IQ tests. (Indeed, Gopnik studied one unrelated child with the syndrome who routinely received the best grade in his mainstream math class.) It is their language that is impaired, but they are not like Broca’s aphasics; the impression is more of a tourist struggling in a foreign city. They speak somewhat slowly and deliberately, carefully planning what they will say and encouraging their interlocutors to come to their aid by completing sentences for them. They report that ordinary conversation is strenuous mental work and that when possible they avoid situations in which they must speak. Their speech contains frequent grammatical errors, such as misuse of pronouns and of suffixes like the plural and past tense:
    It’s a flying finches, they are.
    She remembered when she hurts herself the other day.
    The neighbors phone the ambulance because the man fall off the tree.
    They boys eat four cookies.
    Carol is cry in the church.
     
    In experimental tests they have difficulty with tasks that normal four-year-olds breeze through. A classic example is the wug -test, another demonstration that normal children do not learn language by imitating their parents. The testee is shown a line drawing of a birdlike creature and told that it is a wug . Then a picture of two of them is shown, and the child is told, “Now there are two of them; there are two _____.” Your typical four-year-old will blurt out wugs , but the language-impaired adult is stymied. One of the adults Gopnik studied laughed nervously and said, “Oh, dear, well carry on.” When pressed, she responded, “Wug…wugness, isn’t it? No. I see. You want to pair…pair it up. OK.” For the next animal, zat , she said, “Za…ka…za…zackle.” For the next, sas , she deduced that it must be “sasses.” Flushed with success, she proceeded to generalize too literally, converting zoop to “zoop-es” and tob to “tob-ye-es,” revealing that she hadn’t really grasped the English rule. Apparently the defective gene in this family somehow affects the development of the rules that normal children use unconsciously. The adults do their best to compensate by consciously reasoning the rules out, with predictably clumsy results.
    Broca’s aphasia and SLI are cases where language is impaired and the rest of intelligence seems more or less intact. But this does not show that language is separate from intelligence. Perhaps language imposes greater demands on the brain than any other problem the mind has to solve. For the other problems, the brain can limp along at less than its full capacity; for language, all systems have to be one hundred percent. To clinch the case, we need to find the opposite dissociation, linguistic idiot savants—that is, people with good language and bad cognition.
    Here is another interview, this one between a fourteen-year-old girl called Denyse and the late psycholinguist Richard