Lexical noun phrases in texts written by deaf children and adults with different proficiency levels in sign language

We report an analysis of lexical noun phrases (NPs) in narrative and expository texts written by Dutch deaf individuals from a bimodal bilingual perspective. Texts written by Dutch deaf children and adults who are either proficient in Sign Language of the Netherlands (SLN) or low-proficient in SLN were compared on structures that either overlap in Dutch and SLN (presence of overt subject and object NPs, NP modifiers, and NP-internal agreement), or are absent in SLN (articles). We found that deaf participants experienced significant difficulty with lexical NPs. Further, deaf proficiently signing children (but not adults) more often omitted obligate articles than deaf low-proficiently signing children. Deaf proficiently signing children and adults did not differ from low-proficiently signing children and adults, however, in the use of NP modifiers, NP-agreement errors and omissions of obligatory NPs. We conclude that proficiency in sign language seems to affect particularly those aspects that differ substantially across sign language and oral language, in this case, articles. We argue that adopting a bimodal bilingual approach is important to understand the writing of deaf children.