  The q-deformation of harmonic oscillators is shown to lead to q-nonlinear
vibrations. The examples of q-nonlinearized wave equation and Schr\"odinger
equation are considered. The procedure is generalized to broader class of
nonlinearities related to other types of deformations. The nonlinear
noncanonical transforms used in the deformation procedure are shown to preserve
in some cases the linear dynamical equations, for instance, for the harmonic
oscillators. The nonlinear coherent states and some physical aspects of the
deformations are reviewed.
