A micro-electrical-mechanical system (MEMS) guided wave device includes a plurality of electrodes arranged below a piezoelectric layer (e.g., either embedded in a slow wave propagation layer or supported by a suspended portion of the piezoelectric layer) and configured for transduction of a lateral acoustic wave in the piezoelectric layer. The piezoelectric layer permits one or more additions or modifications to be made thereto, such as trimming (thinning) of selective areas, addition of loading materials, sandwiching of piezoelectric layer regions between electrodes to yield capacitive elements or non-linear elastic convolvers, addition of sensing materials, and addition of functional layers providing mixed domain signal processing utility.