Abstract
Mother Tongue-Based Multilingual Education teachers have been searching for answers to address problems on the references on the textbooks used in the said subjects in Manobo Village Elementary School where the learners were belonging to the Indigenous People. On the other hand, pupils were assessed as low performing particularly in subjects using English as a medium of instruction since they were used of their first language. This study Manobo - Dulangan Lexicography: A Reference to a Mother-Tongue Based System aimed to assess the effect of the materials in the pretest and posttest of Manobo Village Elementary School pupils. It also discussed the significant difference between the mean gain of the control group and experimental group. The respondents of the study were sixty Manobo Grade 3 pupils. The data were gathered through a random sampling procedure. Meanwhile, the level of achievement of the control group and experimental group during pre-test is low. The level of achievement of both groups had improved in the posttest. It shows that the students had improved their understanding after the lessons had been taught to them. The overall mean gain scores of the control and experimental groups showed that there that there was an improvement between the two groups.
