The present preliminary study looks at speech units and pauses' quantity, duration and distribution in native (L1) vs non-native (L2) spontaneous speech. 6 English L1 -French L2 speakers (2 females) were recorded in their L1 and L2 on a conversation task. 3 speakers had an elementary L2 proficiency level, the other 3 were advanced. We looked at 1) the effect of speaking an L2 vs an L1 (within-speaker analysis) and 2) the effect of the proficiency level (betweenspeaker analysis) on the quantity, distribution and duration of silent and voiced pauses and the quantity and duration of Inter Pausal Units (IPU). Our results show that the IPU tend to be more numerous and shorter in L2 but those differences do not reach significance. Pauses are more numerous in L2 regardless of the proficiency level and the difference between L1 and L2 is less important in the advanced group. These tendencies concern mainly the quantity and less so the duration and distribution. Additionally, we notice a greater diversity in the type of pauses in L2. These observations shed light on the reality of interlanguage and the methodological issues involved in its description. Implications for L2 speech analysis and evaluation are discussed.