[en] Inelastic neutron scattering measurements have been performed on the intermetallic compounds Pr₂Co₁₂Fe₅ (and Y₂Co₁₂Fe₅) on the IN4 time-of-flight spectrometer at the Institut Laue-Langevin, Grenoble. The data on the yttrium-based compound have been used to estimate the phonon scattering. A broad peak is detected at 18 meV, whose deduced Q dependence (when only the magnetic contribution is considered) is consistent with the form factor of Pr³⁺ ions; in the high-Q region, the same peak displays a clear phononic character. The experimental results are analysed by a molecular field model including exchange and crystal-field contributions, and the derived value for the exchange parameter is consistent with the trend inferred by studying Pr₂Co₁₇ and Pr₂Fe₁₇. A possible mechanism for the generation of the large volume magnetostriction, to be checked by further experiments, is suggested