The authors treat smoothing and local existence theory of generalized nonlinear Schrödinger equations where nonlinearities up to first order derivatives are allowed, and where the linear part may be nonelliptic. Those equations may model e.g. problems in water wave theory. One of their main results concerns the removal of size restriction for the initial data (which have to lie in certain Sobolev spaces) of local solutions; these solutions inherit a local smoothing effect in space time. The method consists in introducing the space derivatives of wave function as new variables, writing the original equation as a system, and using results of earlier papers of the same authors. The system has the advantage that the crucial term vanishes for \(t=0\) if a solution of the original equation is inserted.