Developing very short computerised early vocabulary assessments in a multilingual setting

The MacArthur-Bates Communicative Development Inventories (CDIs) are one of the most widely adapted sets of parent-report instruments for assessing young children's early vocabulary acquisition (Fenson et al., 2007; Frank, Braginsky, Marchman, & Yurovsky, 2021). The MacArthur-Bates Communicative Development Inventories (CDIs) are valid and reliable not only with children who are developing typically (Fenson et al., 2007, 1993; Pan, Rowe, Spier, & Tamis-Lemonda, 2004; Rescorla, Ratner, Jusczyk, & Jusczyk, 2005; Law & Roy, 2008), but also with children developing atypically (Galeote, Checa, Sánchez- Palacios, Sebastián, & Soto, 2016; Luyster, Lopez, & Lord, 2007; Mayne, Yoshinaga-Itano, Sedey, & Carey, 1998; Mayne, Yoshinaga-Itano, & Sedey, 1999; D. Thal, DesJardin, & Eisenberg, 2007). The CDIs provide extensive insights into children's vocabulary sizes, yet they rely on parents' knowledge of their children. Furthermore, the completion of each CDI is time-consuming as the parent has to assess their child's word knowledge item-by-item, often amounting to 600 words or more. Although previous efforts were made to develop 100-item short-form versions, it is time-consuming to develop short-forms for each language, and their administrations remain a considerable time investment for parents when completing such forms. The process of completing CDIs is made even more laborious, when having to fill out CDIs for several languages, for children exposed to more than one language, such as most children from Malaysia, a linguistically diverse country, where bi- and multilingually-exposed children constitute a significant proportion of the population. Hence, the objective of the current project is two-fold: 1) to collect the first Malaysian early vocabulary data using an adaptation of the CDI forms and provide insights into Malaysian children's early language development; and 2) to develop CDI-based novel vocabulary assessment tools, with the aim of improving the administration of CDIs and examining the viability of a CDI-based toddler-directed word comprehension assessment tool using tablets to supplement the parental reports. The first part of the thesis adopted the MacArthur-Bates Communicative Developmental Inventories - Malaysian version (MCDI-M), a trilingual form developed by Low (2009) to examine the early vocabulary trajectories of young Malaysian children, along with a quantification of environmental effects on the language development of these children, and examining the composition of early vocabularies, i.e., the acquisition of nouns and verbs. The second part of the thesis introduced two novel early vocabulary assessment tools. First, a language-general, Bayesian-inspired item response theory-based framework was developed - based on prior work by Mayor and Mani (2018) and Makransky, Dale, Havmose, and Bleses (2016) (MM-IRT) in order to reduce the number of items needed to assess children's language. This framework was evaluated using data sampled from the Wordbank database in English, Danish, Mandarin and Italian. The framework was then applied to two sets of MCDI-M dataset to evaluate the possibility of using this set of innovations in the context of multilingual children in Malaysia. Second, a toddler-based version of CDIs, using tablets, was evaluated with the aim of directly assessing each child's language skills, and was evaluated empirically. In sum, the first part of this thesis found the use of MCDI-M as an effective early vocabulary assessment tool for Malaysian children, whereas the second part of this thesis paved the way towards the application of rapid yet robust language assessments powered by MM-IRT, to be used in clinical settings, and demonstrated the viability and convergence of using tablets for direct-measure of language skills.