Teachers and psychologists need an instrument to assess learners’ language
proficiency in mathematics to enable them to plan and evaluate interventions and to facilitate best practice in mathematics classrooms. We describe the
development of a mathematics vocabulary questionnaire to measure learners’
language proficiency in mathematics in the intermediate phase. It covers all the steps from designing the preliminary questionnaire to standardising the final instrument. A sample of 1 103 Grades 4 to 7 Afrikaans-, English- and Tswana-speaking learners in North West Province completed the Mathematics
Vocabulary questionnaire (Primary) (MV(P)), consisting of 12 items. We analysed the data by calculating discrimination values, performing a factor analysis, determining reliability coefficients, and investigating item bias by language, gender, and grade. We concluded that there was strong evidence of
validity and reliability for the MV(P).