The spectrum of optical phonons (including localized transverse and longitudinal optical phonons, as well as their overtones and surface optical phonons) in semiconductor CdS, PbS, ZnS, ZnO, CuS, and Ag2S nanocrystals formed by the Langmuir-Blodgett technique on solid substrates is studied using non-resonant, resonant, and surface-enhanced Raman as well as Infrared spectroscopies.