This study explores the link between foreign language aptitude and working and phonological short-term memory ability; the role of foreign language aptitude in succesful communicative language teaching combined with focus-on-form instruction; and language aptitude and phonological short-term memory stability throughout the learning process. Students of a regular Hungarian and an English-Hungarian bilingual secondary school participated in the experiment. Findings show an impact of language learning experience on language aptitude. Foreign language aptitude does not play a major role in focus-on-form instruction.