EMA was used to study the coordination of the articulatory gestures for C1 and C2 in onset clusters, firstly as a function of the segmental make-up of the clusters, and secondly as a function of stress and prosodic boundary conditions. The segmental results, which compared German and French, indicated a much lower degree of overlap of C1 and C2 for C2=/n/ compared to C2=/l/ (with C1=/p, b, k, g/). Overlap was also less for voiceless compared to voiced C1 for German. Prosodic boundary strength affected the duration of the C1 articulatory constriction more strongly than that of C2, while, conversely, differences in lexical stress affected C2 more strongly than C1. The coordination relations between C1 and C2 were, however, not systematically affected by prosodic conditions. Nor did the different clusters studied (/kl, kn, sk/) appear to differ in their internal cohesiveness. The results are discussed with respect to how articulatory coordination is constrained to allow acoustic recovery of segmental information by the listener; the possibility of cross-language differences in these constraints is raised.