This study investigated three of the issues recently raised in connection with the traditional concept of foreign language aptitude: the relationship between foreign language aptitude and working memory and phonological short-term memory capacity, the role of foreign language aptitude in predicting success in the framework of focus-on-form foreign language instruction, and the stability of language aptitude and phonological short-term memory in the course of language learning. The participants of our research were 40 students of an English-Hungarian bilingual secondary school and 21 students in a regular Hungarian secondary school. Language aptitude was assessed both at the beginning and the end of the academic year. Our results support the existence of an effect of language learning experience on language aptitude. We also concluded that foreign language aptitude does not play a highly important role in communicative language teaching combined with focus-on-form instruction.