The Relationship Between Child Language Proficiency and Language of Treatment on the Outcomes of Bilingual Children with Developmental Language Disorder

More than 8.5 million children in the USA speak Spanish at home with about a half million experiencing Developmental Language Disorder (DLD), a disorder in language learning and use that cannot be attributed to limited language exposure, autism, intellectual disability, hearing impairment, etc. One key challenge in serving bilingual children with DLD is the mismatch between the language(s) they speak and the availability of Speech Language Pathologists (SLPs) who can provide services in those languages. While it seems self-evident that a monolingual child should be treated in their first language, currently there is no guidance for SLPs as to the language of intervention for bilingual children. Hence, a critical question is what language(s) of treatment will best serve children with DLD with different proficiency profiles in their development of both Spanish and English. The first question is whether gains in the treated language(s) are influenced by the child's proficiency in each language (Aim 1). Cross-linguistic transfer has been documented in priming studies suggesting that underlying syntax representations are interconnected. Transfer effects may make it possible for a child to improve in both languages as a result of treatment in one language, provided that the child has adequate levels of knowledge to connect the information provided in treatment across both languages. The clearest evidence of transfer can be derived from assessing gains in the untreated language when treatment is presented monolingually (Aim 2). Our own preliminary data suggest that recast therapy can result in gains in both English and Spanish for children treated in just one language. In this study, the investigators carry out a randomized controlled trial, enrolling 120 children with DLD between the ages of 4 and 6 who score below 40% correct on the use of conditional adverbial clauses (if-then) and Complement clauses (e.g., he wonders who will be there…). Children receive one of three possible treatments (English-only, Spanish-only, bilingual) for one grammatical structure for 9 weeks, and then outcomes are re-assessed for both structures in both languages. The second grammatical structure is then treated for 9 weeks, and outcomes are assessed a third time. Comparison of different treatment approaches will inform our understanding of what is the best approach to therapy for bilingual children with a particular proficiency profile. Comparison of gains across languages and targets will allow us to determine the role of cross-linguistic transfer in language learning and to inform theoretical accounts of language representation in the developing bilingual child.

Inclusion criteria

• parent concerns and/or a history of receiving services in the public schools
• age-specific cutoffs for the morphosyntax subtests for their best language (English or Spanish) on the Bilingual English Spanish Assessment. The cut-off score for best language for 4-year-olds is 84, for 5-year-olds is 85, and for 6-year-olds is 81. Using the best-language approach, these scores have a sensitivity over 90% and specificity over 80% for children between 4;0 and 6;11 years of age , which is considered acceptable for studies of diagnostic accuracy.
• nonverbal IQ, as measured by the Kaufman Brief Intelligence Test-2, matrices subtest, will be at or above a standard score of 70.
• pass a hearing screening test
• participants must be bilingual, that is children must be producing at least simple sentences in spontaneous speech in both Spanish and English, or understand English and Spanish.
• participants must be able to benefit from treatment for both conditional adverbial clauses and complement clauses, as evidenced by accuracy below 40% on 10-item elicited production probes in both languages

Exclusion criteria

• 1) children with significant sensory-motor concerns or psychiatric disorders per parent report will not be enrolled.