Generalized Love-type wave propagation in a nonlinear, heterogeneous, isotropic, low-velocity intermediate layer of uniform thickness lying between two nonlinear, homogeneous, elastic different half spaces is examined. The heterogeneity of the layer is considered to result from the exponential change of rigidity and density in the thickness direction. Nonlinear self-modulation of waves is characterized by a nonlinear Schrödinger equation with the aid of multiple scales asymptotic method. The influence of both nonlinearand heterogeneous characteristics of the slow intermediate layer on the existence of bright and dark soliton Love-type waves is investigated numerically. Furthermore, the considerable effect of the layer’s linear and nonlinear heterogeneity properties on the nonlinear evolution of bright and dark solitary waves is graphically shown.