There is growing evidence that the grammatical errors reflected in the speech of young children are often related to the nature of the input in the ambient language. Although theoretical frameworks differ in the degree to which input plays a role, there is acknowledgment that children require more input than previously assumed to resolve apparent…

Children with developmental language disorder (DLD) have significant deficits in language ability that cannot be attributed to neurological damage, hearing impairment, or intellectual disability. The symptoms displayed by children with DLD differ across languages. In English, DLD is often marked by severe difficulties acquiring verb inflection.…

We tested four predictions based on the assumption that optional infinitives can be attributed to properties of the input whereby children inappropriately extract non-finite subject-verb sequences (e.g. "the girl run") from larger input utterances (e.g. "Does the girl run?" "Let's watch the girl run"). Thirty children…

Purpose: Our purpose was to test the competing sources of input (CSI) hypothesis by evaluating an intervention based on its principles. This hypothesis proposes that children's use of main verbs without tense is the result of their treating certain sentence types in the input (e.g., "Was 'she laughing'?") as models for declaratives…

Purpose: To examine the role of linguistic input in how young, typically developing children use the 3rd person singular -"s" (3S) inflection. Method: Novel verbs were presented to 16 young children in either 3S contexts (e.g., "The tiger heens") or nonfinite (NF) contexts (e.g., "Will the tiger heen?"). The input was further manipulated for…

Purpose: To propose that the diagnostic category of "expressive language disorder" as distinct from a disorder of both expressive and receptive language might not be accurate. Method: Evidence that casts doubt on a pure form of this disorder is reviewed from several sources, including the literature on genetic findings, theories of language…