Influence of certain language and communication environments in early childhood on the development of language in deaf individuals.

Four groups of deaf subjects between the age of 10-0 and 18-11 years were tested, employing the Test of Syntactic Ability, and the language subtests of the Stanford Achievement Test, in a study of the influence of early language and communication environment on later syntactic language ability. The groups, 18 subjects in each, were dichotomized by whether the parents were hearing or deaf and further subgrouped by the language ability of the parents if the parents were deaf, and by the amount and intensity of oral preschool training provided by the parents if the parents were hearing. The groups were labeled by the type of language used with them in infancy and early childhood: manual English, average manual, intensive oral, and average oral. Results showed significant superiority of the manual English group over the two oral groups on five of the six major test structures of the Test of Syntactic Ability. On the Stanford Achievement Test, the manual English group performed significantly better than the other three groups on all four subtests. The two manual groups performed significantly better than the two oral groups on every test measure employed.