When event knowledge overrides word order in sentence comprehension: Learning a first language after childhood

Limited language experience in childhood is common among deaf individuals, which prior research has shown to lead to low levels of language processing. Although basic structures such as word order have been found to be resilient to conditions of sparse language input in early life, whether they are robust to conditions of extreme language delay is unknown. The sentence comprehension strategies of post-childhood, first-language (L1) learners of American Sign Language (ASL) with at least 9 years of language experience were investigated, in comparison to two control groups of learners with full access to language from birth (deaf native signers and hearing L2 learners who were native English speakers). The results of a sentence-to-picture matching experiment show that event knowledge overrides word order for post-childhood L1 learners, regardless of the animacy of the subject, while both deaf native signers and hearing L2 signers consistently rely on word order to comprehend sentences. Language inaccessibility throughout early childhood impedes the acquisition of even basic word order. Similar to the strategies used by very young children prior to the development of basic sentence structure, post-childhood L1 learners rely more on context and event knowledge to comprehend sentences. Language experience during childhood is critical to the development of basic sentence structure.