This study examines language aptitude determinants, with a focus on working memory (WM) skill. Language aptitude in Turkish university students with advanced English competence was measured via computerised aptitude test: the LLAMA. WM capacity appears to match with the global language aptitude score rather than with its subcomponents, save for grammatical inferencing. Inquiry further identifies WM and language aptitude as distinct constructs. Finally, WM capacity still plays a crucial role in a renewed aptitude construct, yet these two cognitive skills are not identical.