This thesis investigated the vocabulary skill of bilingual adolescents and young adults with two studies. Study 1 examined the contributions of English phonological awareness and morphological awareness to English vocabulary in 80 Spanish-English and 117 Chinese-English bilingual adolescents educated in Canada. Using Structural Equation Modelling, the study showed that English derivational awareness, word reading and length of residence contributed to English vocabulary for both language groups. In addition, for the Chinese-English bilingual group, English phonological awareness contributed to English vocabulary both directly and indirectly through the mediation of English word reading. Study 2 compared the contributions of Chinese compound awareness and homograph awareness to Chinese vocabulary between Chinese L1 young adults educated in China and in Canada. Participants included 96 and 66 first-year university students in China and Canada, respectively. Using hierarchical regression analyses, Study 2 showed that Chinese homograph awareness and character reading contributed to Chinese vocabulary for both groups of Chinese L1 young adults; however, the contribution of Chinese compound awareness was not significant. The association of Chinese homograph awareness with Chinese vocabulary was not significantly different between the two groups, whereas the association of Chinese character reading with Chinese vocabulary was stronger for the Chinese L1 young adults in China. Overall, the thesis highlights the importance of morphological awareness to vocabulary across English and Chinese for older students.Ph.D
