We report temperature-dependent Raman spectra of CeFeAsO 0.9F0.1 from 4 to 300K in the spectral range of 60-1800cm- 1 and interpret them using estimates of phonon frequencies obtained from first-principles density functional calculations. We find evidence for strong coupling between the phonons and crystal field excitations; in particular the Ce3 + crystal field excitation at 432cm - 1 couples strongly with the Eg oxygen vibration at 389cm- 1. Below the superconducting transition temperature, the phonon mode near 280cm- 1 shows softening, signaling its coupling with the superconducting gap. The ratio of the superconducting gap to T c, thus estimated to be ∼ 10, suggests CeFeAsO 0.9F0.1 to be a strong coupling superconductor. In addition, two high frequency modes observed at 1342 and 1600cm- 1 are attributed to electronic Raman scattering from the (x2-y 2) to xz /yz d-orbitals of Fe. © 2010 IOP Publishing Ltd.