Development of a Mathematics Vocabulary Test: Evidence of Validity and Reliability in a Multilingual Context

The aim of this study was to develop the Mathematics Vocabulary Test (MVT)—an instrument to identify young children with a limited mathematics vocabulary—in a multilingual majority country—South Africa. This study consists of two substudies with children aged 3–8.5 years (N = 988, n_girls = 429). In Study 1, a 26-item MVT was developed by multiprofessional expert panels and piloted in four languages, isiZulu (n = 229), Sesotho (n = 83), English (n = 89), and Afrikaans (n = 216). Study 1 provided evidence of content validity, and the MVT was further revised based on the results. In Study 2, additional samples were assessed with the revised version of the MVT in English (Stage 1, n = 270) and isiZulu (Stage 2, n = 101) to provide further evidence of reliability and validity for these two language versions of the test. Confirmatory factor analyses supported structural validity of a unidimensional structure, including 20 items in the English version and 16 items in the isiZulu version. The structure of the English MVT showed stability across time (T2 5 months after T1). Both versions showed good reliability in terms of internal consistency. Our findings also provided evidence of concurrent and known-group validity for both language versions, as well as predictive validity of the English version of the test. The English and isiZulu MVT can be used as a measure of mathematics vocabulary in educational practice and research with young children.