Raman scattering study and lattice-dynamics calculations in YTiO3: Precursor of the magnetic phase transition in the phonon anomalies

•The anomalous behavior of the resonant frequencies and widths of the Raman modes in YTiO3 sets on well above the ferromagnetic transition at TC=30K.•The vibrational character of the Raman modes in YTiO3 is comprehensibly identified by the theoretical shell-model lattice-dynamics calculations.•The relative enhancement of the tetragonal (E type) modes with respect to the trigonal (T2 type) “scissors” modes is observed with decreasing temperature.•The following phonon anomalies indicate the orbital structure refinement on the route to the ferromagnetic ground state in YTiO3.