Bone conduction (BC) is the conduction of sound to the inner ear primarily through biological tissues. BC has been applied to hearing aids, earphones and other audio devices, such as smart glasses, present stimuli to the face. One of the important characteristics of BC is the occlusion effect (OE): a phenomenon whereby low-frequency sounds are perceived as being enhanced when the ear canal is occluded. Studies examining OE in facial parts have revealed that the OE in some facial parts (the nasal bone, infraorbital region, jaw angle) was equal to or better than OE in the conventional parts (the mastoid process and condylar process). In this study, we evaluated effects of OE on speech perception. We investigated the effects of OE on monosyllable articulation in the mastoid process, condylar process, nasal bone, and infraorbital region. The results showed that OE increased articulation and can be applied to facilitating voice communication. [ABSTRACT FROM AUTHOR]