Paper Title
Pedagogical Knowledge of Differentiated Instruction in English Language Teaching

Abstract
This study explored pedagogical knowledge of differentiated instruction (DI) in the teaching of English language among English language teachers at one gifted school in Malaysia, and examined the extent to which the practice of DI had an effect on the gifted students’ motivation and acquisition of the English language. Three important notions informed the theoretical framework and research design of this study: Vygotsky’s sociocultural theory of teaching and learning, Borg’s framework of teacher cognition, Tomlinson’s model of DI, and Dornyei’s L2 motivational teaching framework. Guided by these theories, an exploratory sequential mixed method case study research design was employed. This research design elicited both qualitative and quantitative data types. Qualitative data included teacher interviews, fieldnotes, and analysis of lesson plans. These multiple sourced data were coded and subjected to a thematic analysis using Atlas.ti 9. Meanwhile, quantitative data was derived from two data sources: a student questionnaire, and students’ scores on an English language test. Descriptive analysis calculate the students’ scores on motivation and achievement. Inferential analyses involving t-test, one-way anova, multiple regression, and pearson’s correlation coefficient determine the relationships between DI, motivation, and achievement. The quantitative findings are triangulated in the final analysis to support findings from the qualitative data in explicating the relationship between DI and the gifted students’ learning motivation and acquisition of the English language. In sum the study revealed four important findings. Firstly, it was found that having the right teacher knowledge about DI is imperative for appropriate differentiation strategies to be employed. Secondly, there was clearly a corresponding relationship between the employment of DI with high students’ motivation but not with their performance in English. Thirdly, five constructs of DI that were identified to have the most significant impact on student motivation were content, product, interest, teacher’s roles, and learning profile. Finally, the fourth finding revealed low significant relationship between motivation and language scores. In conclusion, although DI did not have a significant relationship with student achievement, nonetheless, it enhanced student motivation, and promoted development of appropriate differentiation strategies for learning that better suit students.