This study investigates the discrimination of a synthesized non-pharyngealized/pharyngealized place-of-articulation contrast in Arabic [si]-[s»i], presented to Arabic-speaking subjects and French-speaking subjects. An identification task showed group differences in the location of die category boundary, reflecting language-specific experience. An AX discrimination task revealed cross-language differences in the phonemic status of the contrast and that levels of discrimination performance were strongly associated with their assimilation patterns.