The hypotheses of the study were: (1) The instructional treatment yield equal level of learning outcomes as measured by achievement scores in English, Hindi, Assamese and self-esteem separately. (2) The different habitation out comes as measured by achievement scores in English, Hindi, Assamese and self-esteem separately. (3) Comparable achievement scores separately in English, Hindi, Assamese and self-esteem are yielded by students with educated and uneducated family background. (4) The difference in performance as measured separately by achievement score in English, Hindi, Assamese and self-esteem through co-operative mastery learning and conventional group learning are not qualified by habitat status. (5) The difference in the performance as measured separately by achievement scores in English, Hindi, Assamese and self-esteem through co-operative mastery learning and conventional group learning are not qualified by educated or uneducated family background. (6) The effect of tribal and non-tribal habitat does not qualify the separately achievement scores in English, Hindi, Assamese and self-esteem of students with educated or uneducated family background. (7) The treatment group yield comparable separately achievement scores in English, Hindi, Assamese and self-esteem for tribal and non-tribal groups coming from educated and uneducated family background. 

The sample comprised 200 students of V grade from four schools of Golakganj selected by random sampling method.

Self-esteem Inventory by Stanly Coppersmith and Criterion Referenced Test and Formative Unit Test on three languages developed by researcher were used for data collection.

2x2x2 factorial design was used by researcher. Treatment was given simultaneously in the three languages. The duration of treatment was one month.

The data were analyzed by Mean, SD, t-test. 

(1) Co-operative mastery learning strategy yielded higher achievement gain scores than conventional group learning for fifth grade students separately in English, Hindi, Assamese languages and self-esteem. (2) Non tribal fifth graders yielded higher achievement gain score than tribal fifth grade students separately in English, Hindi and Assamese languages but no difference for self-esteem score. (3) No difference was found between achievement gain scores of students of fifth grader coming from educated and uneducated family background separately in English, Hindi and Assamese languages and self-esteem score. (4) No interaction was found among the instructional mode, habitations and family background with regard to achievement gain scores separately in English and Assamese languages and self-esteem but found to operate independent of each other for Hindi language learning. (5) Habitation and family background were found to operate independent of each other with regard to achievement gain scores of fifth grade students separately in English and Assamese languages. (6) No interaction was found between instructional mode and family background for achievement gain scores of fifth grade students in English language. (7) Fifth graders coming from educated or uneducated family background yielded equal achievement gain score in Hindi under co-operative mastery learning and conventional group learning instructional mode. (8) Equal achievement gain scores were found for tribal and non- tribal fifth graders for the two instructional modes (CML and CGL). (9) Cooperative mastery learning yielded almost similar achievement gain scores in English language for tribal and non-tribal fifth graders. (10) Tribal fifth graders learning through cooperative mastery learning strategy yielded higher achievement gain scores in English language as compared to non-tribal getting instruction through conventional group learning. (11) Non-tribal fifth graders of co-operative mastery learning group attained higher achievement gain scores in English language as compared to their tribal counterparts of conventional group learning. (12) Tribal fifth graders yielded higher achievement gain scores in English language in cooperative mastery learning situation than in conventional group learning. (13) For non-tribal fifth grades of co-operative mastery learning instructional mode yielded higher achievement gain scores as compared to conventional group learning. (14) For co-operative mastery learning and conventional group learning, gain scores in self-esteem of fifth grade tribal and non-tribal were not found statistically different. (15) Gain scores in self-esteem of fifth graders coming from educated families or uneducated families were not different under co-operation mastery learning or conventional group learning instructional modes. (16) Co-operative mastery learning strategy in Hindi was found to have maximum effect size, second being in English and quite high otherwise, but third in Assamese language.