Longitudinal and transverse charge and mass current fluctuation spectra are calculated self-consistently for all wave numbers $q$ and frequencies $\ensuremath{\omega}$. The theory suggests a new generalized random-phase approximation which interpolates between the (large-$q$) kinetic regime and (the small-$q$) collision-dominated regime. The relaxation kernel governing the decay of current excitations at small wave numbers is approximated by a mode-coupling expression. The theory uses as input the pair potentials and the static pair and triplet correlation functions. For the latter a modified superposition approximation is employed. The results are compared with computer-simulation data.