  Infrared-active phonons in LaMnO_{3+\delta} were studied by means of the
reflection and transmission spectroscopy from 50 to 800 cm^{-1} at room
temperature. Powder and ceramic samples of the phases of Pnma-2 (\delta=0.02),
Pnma-1 (\delta=0.08), and R3c (\delta=0.15) were investigated. Besides,
energies of the dipole-active phonons in Pnma-2, Pnma-1 phases were obtained by
lattice-dynamics calculations. The transformations of IR-active phonons with
the increase of \delta in the sequence of Pnma-2, Pnma-1, R3c are discussed.
