Based on a fully Galilean electrodynamics of ferroelectric dielectric deformable bodies and the equations for weak fields linearized about an initial rigid‐body ferroelectric state with hexagonal symmetry deduced in a previous paper (in which a symmetry breaking was exhibited), a rather complete study of coupled, dispersive, and attenuated bulk wave‐propagation modes is presented. Apart from usual optic modes, resonance couplings and repulsion of branches for acoustic modes and polaritons are exhibited for various directions of propagation (longitudinal, orthogonal, and arbitrary settings of the bias polarization field). A birefringence effect for polaritons and an acoustical activity are placed in evidence. In addition to the analytical study which leans on the use of small coupling parameters in order to allow for a manageable discussion of the dispersion behavior for both nondissipative and dissipative processes, and to illustrate these theoretical results, numerical estimates and plots of the most interesting coupling effects are given for a test material such as ferroelectric barium titanate.