Genetics and the development of language disabilities and abilities

Genetic research has been slow to come to the field of language development, but during the past decade it has begun to make up for lost time. Research suggests that language disabilities in children are among the most highly heritable disorders, fuelling optimism for finding specific genes. Research has gone beyond merely demonstrating heritability in three ways. First, there are strong genetic links between language disabilities and abilities: what we see as language problems may be the extremes of dimensions (abilities) rather than aetiologically distinct disorders (disabilities). Second, multivariate genetic research suggests that about half of the genetic effects on language disability overlap with non-verbal cognitive disability and about half of the genetic effects are specific, providing support for non-specific language impairment as well as for specific language impairment. Third, specific genes are being identified which will be used to address such issues with much greater precision.