Results of luminescence and Raman spectroscopy studies of PLZT-x/95/5 (1≤x≤4mol%) ceramics with the emphasis on the phonon dynamics are presented. The luminescence spectrum of Cr3+ impurity ion in these ceramics is characteristic of strong crystal field. The dominant effect is two intense luminescence lines corresponding to 2E→4A2 transitions of Cr3+ ion. The determination of the crystal field parameters suggests that the zirconium site is the only possible site for the trivalent Cr3+ chromium impurity. Vibronic sidebands originating from dipolar interactions between electronic states of excited Cr3+ ions and electrical dipoles that occur during torsional and stretching vibrations, are present in the luminescence spectra. Presence of Cr3+ ions excited states due to the environment created by the lanthanum doping may be related to the Raman activation, in the ferroelectric phase of the ceramics, of two zone-boundary acoustic phonons.