Project Summary
More than 8.5 million children in the USA speak Spanish at home (U.S. Census Table S1601, 2020) 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.
(Norbury et al., 2016; Tomblin et al., 1996). 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 (Kohnert et al., 2005). 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.
We ask first 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, we 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 subject relative clauses (e.g., the doll that the girl loved…). 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.
