Abstract: The biaxially oriented multilayered films include a stack (A-B)n of n layer units A-B, where n is greater than or equal to 32 each layer unit A-B having individual layers comprising a first layer A and a second layer B overlying the first layer A. The biaxially oriented multilayer films include intralayer voids within a portion of the individual layers in the stack. The intralayer voids have width-to-height aspect ratios from 20:1 to 500:1. The first layers of the layer units have a first composition, and the second layers of the layer units have a second composition. The first composition includes a first thermoplastic and a first polymer immiscible with the first thermoplastic. The second composition includes a second thermoplastic that may be the same as or different from that of the first thermoplastic.