The acquisition of negative forms by a Jordanian Arabic speaker as evidenced in utterances from 19 months of age is examined. The language corpus consisted of selective samples of spontaneous daily speech and biweekly recorded speech sessions. Results suggest that although the subject's negation system is incomplete, it will be acquired by age 5. The findings affirm the developmental nature of the process of acquisition of the Jordanian Arabic negation system and the developmental sequence suggested by previous research, with a rule being modified more than once depending on the subject's developing linguistic competence. The findings do not entirely support the developmental stages proposed by previous research, especially in the cases of anaphoric versus non-anaphoric negation acquisition and intrasentential negation. (MSE)