The main purpose of the study was to determine the effect of Mother Tongue Language-Based (MTLB) instruction on grade two pupils' Mathematics performance. The study utilized a quasi-experimental research design specifically the Pretest Postest Control Group Design. The instruments used were the Mathematics performance test and pupils perception on the use of Mother Tongue Language Based (MTLB) instruction in Mathematics. The participants involved in the study were two groups of grade two pupils. Those who were exposed to English instruction were assigned as the control group and those pupils exposed to Mother Tongue Based instruction (Filipino) were assigned as the experimental group.
The effect of Mother Tongue Language-Based (MTLB) instruction on grade two pupils' mathematics performance was determined by comparing the pupils performance pretest and posttest mean scores. The results revealed that the pupils in experimental group had a pretest mean score almost comparable with the performance pretest mean score of control group. Specifically, before the treatment, both groups were of the same prior knowledge of the subject. Thus, there was no significant difference between the control and experimental group as revealed in their performance pretest. While the performance posttest results revealed that learning took place both for control and experimental groups; however, the pupils' Mathematics performance posttest results from experimental group who used mother tongue based instruction was significantly higher than the Mathematics performance posttest result of those who were in the english instruction control group. Futher, on pupils point of view, they seemed to easily understand Mathematics concepts when their teacher used mother tongue language based (MTLB) instruction than those who used english instruction as revealed by the given survey test. It is therefore desirable for grade 2 teachers to adopt the mother tongue instruction as it makes learners easily acquire knowledge in Mathematics