We consider acoustic propagation in a particle-laden fluid, specifically, a perfect gas, under a model system based on the theories of Marble (1970) and Thompson (1972). Our primary aim is to understand, via analytical methods, the impact of the particle phase on the acoustic velocity field. Working under the finite-amplitude approximation, we investigate singular surface and traveling wave phenomena, as admitted by both phases of the flow. We show, among other things, that the particle velocity field admits a singular surface one order higher than that of the gas phase, that the particleto-gas density ratio plays a number of critical roles, and that traveling wave solutions are only possible for sufficiently small values of the Mach number. i.e., the particle specific heat (at constant pressure) is negligibly small; see Thompson [34, pp. 553-556]. The immediate (practical) consequence of this assumption is τ T = 0 (⇒ the absence of thermal inertia), where τ T ∝ c pp is the thermal relaxation time.