This article considers inter-individual variation in omission rates of the preverbal particle ne in 991 negations produced in conversations between 73 native and non-native speakers of French. It appears that both endogenous and exogenous extralinguistic factors are linked to omission rates of ne. Whereas age and gender were found to have little effect, the degree of extraversion of the speaker, the frequency of use of French and the native/non-native status of the speakers were correlated with omission rates. Among the exogenous factors it appeared that the composition of the dyad was linked to omission rates: non-native speakers interacting with native speakers omitted the ne more frequently than the non-native speakers in conversation with other non-native speakers. The theoretical implications of these findings are discussed.