Speech enhancement apparatus and respirator masks including speech enhancement apparatus, as well as methods of enhancing speech transmission for the wearer of a respirator mask are described herein. In one or more embodiments, the speech enhancement apparatus and methods described herein detect acoustic energy within a first frequency range in the clean air envelope of a respirator mask and deliver compensating acoustic energy outside of the clean air envelope using a speaker. The compensating acoustic energy, in one or more embodiments, exhibits a predetermined attenuated amplitude profile such that the compensating acoustic energy has an amplitude less than 6 dB greater than the acoustic attenuation profile of the mask body over at least 90% of a predetermined attenuated frequency range.