This study investigated the impact of mother tongue on students’ academic performance in English Language in Lagos State Schools. The study adopted descriptive research design. The population of the study will consist of all the secondary school English Language teachers in Ojo Local Government Area of Lagos State. Questionnaires was the major tool for data collection and data collected were analyzed using the statistical tools of frequency counts, simple percentage for the demographic data while the inferential statistics of t-test with the aid of the Statistical Package for the Social Sciences (SPSS) was used to test all the stated hypotheses at 5% level of significance. A total of 40 copies of questionnaires were administered to the respondents. Among other things the result of the study revealed there is a significant relationship between mother tongue and students’ academic performance in English Language in Lagos State Schools, that mother tongue interference has an effect on oral pronunciation in English Language among secondary schools in Lagos State, and that mother tongue interference has an effect on students’ written composition in English language. To this end, the study recommended that teachers need to do more than teaching theories in class. Proper method of teaching and appropriate instructional materials should be adopted to compliment teacher’s knowledge. This goes a long way in influencing teaching and learning process in English language. Materials selected should be commensurable with grade or maturity level of students. This becomes necessary as the result of the study has revealed that mother tongue interference has an effect on students’ written composition in English language.

Keywords: Mother Tongue, Students’ Academic Performance, English Language, Mother Tongue Interference, and Written Composition.

1.2     Statement of the Problem

Poor secondary school students’ academic performance in English language has remained as a major issue among teachers, parents, school administrators, students and the society at large. Attempts have been made by researchers (such as Iroegbu, 2006, Oluwole, 2008, Odeh, Nta, Egbe, Ebuta, 2012, and Awopetu, 2016) to unravel the complexities surrounding poor students’ academic performance in English language. Psychologists (such as Bandura, 1977, Adamolekun, 1987, Ortese, 1998, and Abramson, Metalsky and Alloy, 1989, Anderson, 1983) have put forward a lot of reasons why these disparities in academic achievement exist. A lot of attention had been paid to external factors such as type of school, teaching methods, school location, instructional materials, study habits, teachers qualification and experiences, and so on.

Opinions vary as to why some students excel academically while others appear to be underachievers. Many educationists have consistently attempted to identify the major predictors of individual academic performance. Factors such as intelligence, self concept, gender, study habit, maturation, home background, amongst others, child rearing patterns, peer group influence, socio-economic background and learning environment just to mention a few, have been extensively explored as being responsible for academic achievement, especially in secondary school students (Eyong, David and Umoh, 2014). However, a major factor that may be responsible for poor students’ academic performance in English language may not be totally unconnected to mother tongue interference.

That is, the influence of one language upon another’s phonology, grammar and vocabulary. This phenomenon remains a usual contributor to under performance of students in language studies across disciplines (Ejenihu, 2001).   Therefore, this study seeks to examine the impact of mother tongue on students’ academic performance in English language in Lagos State Schools.

1.3     Purpose of the Study

The general objective of this study is to explore the impact of mother tongue on students’ academic performance in English language in Lagos State Schools. Other specific objectives are:

     i.        To examine the impact of mother tongue on students’ academic performance in English language in Lagos State Schools

   ii.        To assess the effect of mother tongue interference on students’ written composition in English language.

  iii.        To find out the teachers’ perceived problems with mother tongue instruction in Lagos State Schools.

  iv.        To provide plausible recommendations on the use of mother tongue to improve students’ academic performance in English language in Lagos State.

1.4    Research Questions

This study was guided by the following research questions:

a)    What is the impact of mother tongue on students’ academic performance in English language in Lagos State Schools?

b)   What is the effect of mother tongue interference on students’ written composition in English language?

c)    What are the teachers’ perceived problems with mother tongue instruction in Lagos State Schools?

1.5        Research Hypotheses

The research was intended to test the following hypotheses:

H_o1: There is no significant relationship between mother tongue and         students’ academic performance in English language in Lagos State Schools.

H_o2:  Mother tongue interference has no effect on students’ written composition in English language.

H_o3:   Curriculum factor is not a perceived problem with mother tongue    instruction in Lagos State Schools.