This study investigates the effects of native language experience and phonetic properties on the discrimination of labial-velar versus labial and velar contrasts, as well as voicing contrasts in labials, velars, and labial-velars. Research indicates that phonological perceptions are influenced by native language experience and the specific features of sounds, raising the question of how listeners perceive a non-native phonological category that combines two L1 categories, such as labial-velar stops predominantly found in West African languages. Properties of labial-velars raise two main issues: (i) in the place of articulation, labial-velars are characterized by a nearly synchronous combination of labial and velar gestures, potentially being mapped into either category or perceived as distinct; (ii) in the voicing segment, labial-velar voicing distinctions may either resemble voicing in English labials and velars or constitute distinct voicing categories. Added to this perceptual complexity is the notion that heritage language experience confers a phonological advantage over non-native listeners, suggesting a potential perceptual advantage for heritage Yoruba speakers over non-native Yoruba listeners. For this dissertation, 20 native Yoruba, 20 heritage Yoruba, and 20 native English speakers without prior exposure to labial-velars, completed an oddity task. Participants listened to three VCV nonce words embedded in a carrier phrase and identified the odd item or chose whether they were the same. The intervocalic target contrasts were [gb]-[g] and [gb]-[b], [kp]-[k] and [kp]-[p] for place of articulation, and [p]-[b], [k]-[g], and [kp]-[gb] for voicing. Results indicate that (i) the labial feature in labial-velars is more salient than the velar gesture, even in intervocalic positions where cues from both gestures are available; (ii) the discrimination of voicing in labial-velars is more challenging than in labials and velars, particularly for non-native listeners; (iii) contrary to prevailing assumptions in heritage language research, the heritage advantage in segmental phonological perception is not universal but rather contrast-dependent; and (iv) heritage experience may sometimes create a disadvantage in phonological perception. [The dissertation citations contained here are published with the permission of ProQuest LLC. Further reproduction is prohibited without permission. Copies of dissertations may be obtained by Telephone (800) 1-800-521-0600. Web page: http://bibliotheek.ehb.be:2222/en-US/products/dissertations/individuals.shtml.]