Abstract: According to an aspect of the present invention, there is provided a face mask, comprising: a frame defining a respiratory chamber, for receiving nose and mouth portions of a user, between a proximal end of the frame for interfacing with a face portion of the user and a distal end of the frame configured for allowing gas exchange with the environment; a vocal guide defined by a sectional portion of the frame, the guide comprising an arched nose ridge portion, side wall portions extending from the nose ridge portion and a base connecting the side wall portions, wherein the guide is configured with an inwardly-projecting contour located at one or more regions of each of the side wall portions so as to alter an output frequency response of sound waves travelling through the frame for improving speech intelligibility of the mask during use.