The cooperative generation of phonon pulses in semiconductors by groups of inverted quasi-equidistant multilevel bound excitations (electrons and excitons) is studied. Such systems with equidistant spectra exist in chalcogenide glasses with a fractal structure. The cooperative generation of nonequilibrium localized phonons (fractons) can be observed in an experimental study of the relaxation of groups of excited atoms after passing a short laser pulse through the sample. An increase in the absorption coefficient in glass excitation by a short laser pulse of comparatively low power is due to the generation of nonequilibrium coherent localized phonons during the relaxation of nonequilibrium excitations. These coherent nonequilibrium localized phonons essentially change the random-potential topology and, consequently, open up a new channel for interband absorption of light. These transitions simultaneously involve photons and localized phonons. Kinetic equations describing the relaxation of localized electrons are obtained for two cases. The first describes the behavior of bound electrons in shallow quantum wells. The second is related to deep quantum wells. The relaxation process strongly depends on the dynamic symmetry of the bound electron-phonon (or exciton-phonon) system. The solutions of these equations are in agreement with experimental data.