A study into the interplay between first and second language reading motivation and vocabulary development

The present study aimed to examine the cross-linguistic effect of L1 vocabulary, reading motivation and habits on L2 vocabulary, reading motivation and habits. In this respect, proposing a model, the study aims to contribute to the foreign language education and research. Moreover, the study also seeks to contribute to Turkish language studies through illustrating Turkish vocabulary size, reading motivation and habits of university students. With respect to the sample size and data collection tools required by the complex theoretical model proposed, the study employed a quantitative survey research design. The data was collected through vocabulary size tests, reading motivational scales and reading habits questionnaires from a total of 490 participants from the four different state universities. As the complex theoretical model suggested, the model proposed in the study was analyzed with PLS-SEM technique. The results revealed that L1 vocabulary size and reading efficacy were the two predictors of L2 vocabulary size; however, L1 vocabulary size was the best predictor. Whereas L1 reading habits explained L1 vocabulary size, L2 reading habits did not predict L2 vocabulary size. Although participants' most highly endorsed reading motivational dispositions in L1 and L2 were different, only intrinsic reading motivation explained reading habits in L1 and L2. Moreover, L1 reading motivation and habits significantly predicted L2 reading motivation and habits. In this respect, the study suggests that L1 vocabulary size and reading habits are important in the development of L2 vocabulary size and reading habits.