Language Defects Linked to the Grammar of Genes : Science: Researchers say inability to form past tenses or plurals may be inherited. Left-handedness may affect how people process words.
Support is growing for the once-controversial idea that a special segment of the brain is responsible for human ability with languages.
By studying adults with specific language impairments, neuroscientists are beginning to tease apart the complex mechanisms by which the brain processes language and imposes grammatical rules.
Among the unusual and surprising findings reported here Monday at a meeting of the American Assn. for the Advancement of Science were these:
* People who have trouble forming past tenses of verbs or plurals of nouns may have an inherited problem caused by a gene.
* Those with left-handers in their family probably process language somewhat differently than most other people, even if they themselves are right-handed. “These studies promise to tell us much about the organization of the brain and the evolution of languages,” said psycholinguist Myrna Gopnik of McGill University in Montreal.
Gopnik studied three generations of a family in which 16 of 30 members could not form plurals or past tenses. “They will say: ‘Today I walk, yesterday I. . .,’ and they don’t know how to finish,” said Gopnik. “For some reason they don’t build the general rules of language,” such as adding the ed to change walk to the past tense. Similarly, faced with an unfamiliar noun or a nonsense word, they do not know how to add an s to make it plural.
In all other aspects, they are normal. “They get the word order right, and they can pick out bad sentences,” Gopnik said. They simply “cannot build on the symbolic rules of language.” Instead, they must learn each plural and each past tense individually, in the same way that people learn those verbs that have irregular past tenses.
The findings, along with some previous studies, point to a strong genetic component in inheriting the language problem.
A different type of language disability is often demonstrated by left-handers. Psychologists have long known that left-handers have a higher incidence of dyslexia, that they might have superior math skills and that they can be gifted at spatial tasks such as solving visual puzzles. These differences are thought to reflect exposure to unusual hormone levels in the womb, which alter the way the brain is organized early in development.
Psychologist Thomas G. Bever of the University of Rochester reasoned that right-handers in families with many left-handers might also be exposed to such prenatal conditions, producing subtle grammatical problems.
He found that to be the case. “Just having left-handers in your family is a sign that your brain is wired up differently than your right-handed neighbors who have no left-handed relatives,” he said.
