We have created a customisable online tool which researchers, speech & language therapists and teachers can use to better understand the language experiences and language background of bi/trilingual children, and to inform the professional evaluation of their language support needs. The tool’s design was informed by an international, cross-sector Delphi consensus survey (including representatives from 29 countries), the comprehensive review of existing tools, best practice identified in the psychometric literature, and consultation with bilingualism experts (research and practice). The tool consists of an online questionnaire and back-end calculator. The questionnaire can be customised according to professional users’ needs in terms of level of detail, type of respondent and language of administration, and is available in 23 languages, with 5 more to be added shortly (far exceeding our original target of 13). The tool was validated using newly collected data from 299 children from 3 countries (France, the Netherlands, and UK), between the ages of 5 and 9. This includes data from the full questionnaire, as well as direct measures of proficiency in the societal language (French, Dutch, or English) and of relevant cognitive skills. Exploiting advanced quantitative methods, we identified complex associations among the Individual Difference variables provided by the Q-BEx questionnaire, when considered as predictors of language proficiency. These associations indicate different types of profiles practitioners might encounter when assessing multilingual children. We demonstrated the practical benefit of composite indices of Richness of Experience as predictors of language proficiency, and demonstrated how these indices share common and specific information among multilingual children’s societal vs home languages. Using an information-theoretic approach, we identified the optimal level of questionnaire detail required to predict language outcomes in multilingual children (as represented in our validation sample). This evidence will guide professional users to choose the level of detail to implement in the questionnaire, given their needs and constraints. Risk for language impairment is incorporated into Q-BEx via a few simple questions about early language development and current oral skills in each language. A Concern Score is derived to identify children likely to be at risk for language impairment. By recruiting some of the children in the validation sample from speech and language therapy clinics, we were able to demonstrate the usefulness of this Concern Score by how well it flagged independently-known-to-be-at-risk children, and by how well the Concern Score predicted language performance in the societal language in all the children flagged by that score. The Concern Score is incorporated in the individual child reports automatically generated by the Q-BEx platform. These reports also include information about the child’s amount of experience in each language (current and cumulative), parental estimates of the child’s proficiency in each language, and indices of Richness of the child’s experience of each language. Evidence-informed guidance is provided for the interpretation of the reports. The validation of the questionnaire also included a qualitative assessment, analysing the validation study data loss, inconsistencies in data, and identifying unlikely scenarios reported by respondents. We offer recommendations to optimise data accuracy and highlight challenges inherent to the collection of data via questionnaires. The data will be made openly available on the RADA repository once our remaining scientific papers have been accepted for publications. The preprints and R code will appear on the OSF. |