An apparatus for evaluating the tongue strength of a subject during a sucking event includes an insert positioned within a nipple element to provide an output in response to deformation of the nipple element during a sucking event. The output is at least one of resistive force exerted against the subject's tongue and movement measurement of deformation force exerted on the nipple element during the sucking event. The apparatus is configurable to evaluate nutritive sucking (NS) or non-nutritive sucking (NNS) capabilities of the subject. The insert may be a sensing device, a compliance element, an intermediate device or a combination of these. A coupling device is configured to position the insert relative to the nipple element and/or to receive output from the insert. A method includes evaluating tongue strength of a subject during NS or NNS and using inserts providing increasing levels of resistive force to exercise the subject's tongue.