Abstract
Early-grade learners build on their preschool numeracy competence with vocabulary and grammar of their home language as important semiotic tools. In this study, the performance of two samples of Grade 2 learners, who completed the MARKO-D SA interview-based test of number concept development, were assessed. The results showed that participants (n = 72) who completed the Tshivenda version of the test performed better than those who participated in an English version of the sametest (n = 70). The MARKO-D SA instrument comprises pictures and counters along with 48 tasks. The study was undertaken to find out how the participants' responses captured their numerical acuity on five levels of difficulty according to a model of number concept development. Based on studies of the role of English as language of learning and teaching (in foundation phase classrooms where learners do not use English as first language, the study hypothesised that there would be a notable difference in the scores of the two groups of participants: the Tshivenda first language participants' outcomes would be better than the outcomes of those who completed the English test. The study concluded that number concept development of Grade 2 learners was associated with their understanding of the language in which the interview-based test was conducted. The authors argue that the findings have implications for the language of learning and teaching in the teaching of mathematics in the foundation phase.