Individual Differences in Language Development and Disorders
Language co-evolved with the human brain throughout the evolution of Homo sapiens. Most of what we know about language in the brain comes from studies of adults who already have a fully developed language system or who have lost language functions due to brain injury. However, if we want to understand the evolutionof language, our best insight may come from understanding the factors that affect the individual differences in language development and, more specifically, the various types of deprivations that may lead to language disorders.
While it is true that most children do not need to be explicitly taught to speak, all children do need sufficient exposureto language for language to develop normally. The modern infant brain comes equipped with intrinsic sensory/perceptual/motor and statistical learning capacities that are fundamental for developing language. This talk will focus on longitudinal studies that show that the efficiency with which these foundational capacities operate, particularly critical auditory processes, determines individual differences in the proficiency of spoken language learning. This intrinsic system is affected by many different genetic/biological as well as environmental/cultural factors, including most of the types of deprivation being discussed in this symposium.