For low-dimensional systems, symmetry breaking and surface reconstruction are critical for the observation of special vibrational properties of technical significance such as surface optical (SO), anharmonic, and disorder-activated phonon (DAP) modes. First, earlier unobserved modes such as SO and DAP are disclosed for cubic zinc sulfide (ZnS) nanoparticles (NPs) of 3−5 nm size by adopting an experimental process without any stabilizing agent at low temperatures. The emphatic influence of surface defects, in particular, elemental “S” in the perturbation of phonon propagation, is elaborated. Furthermore, studies with surface functionalization and heat treatment provide significant insights into the critical influence of synthesis conditions that possibly withhold such surface modes in the cubic zero-dimensional ZnS in previous reports. The effect of crystal size is also elaborated. Moreover, the experimentally observed SO mode is verified theoretically for different ZnS NPs along with the effect of the dielectric medium. In addition to structural elucidation by high-resolution transmission electron microscopy, electron energy loss spectroscopy, Raman spectroscopy, and temperature-dependent photoluminescence measurements, they provide evidence of nanoscale surface modulation as a necessary condition to evolve such active surface modes in the cubic phase ZnS NPs.