Two experiments were designed to investigate two issues: (a) acoustic correlates in the place of articulation in Mandarin syllable-final nasals, and (b) the contribution of acoustic cues to perceptual saliency for the alveolar-velar nasal contrast. In Experiment 1, an acoustic analysis identified phonetic features adopted by L1 and L2 speakers of Mandarin in Taiwan to distinguish the [n]-[ŋ] pair. Results revealed that spectral differences, found in Mainland Mandarin, were not significant in Taiwan Mandarin, which displayed certain nasal mergers. In Experiment 2, recordings of these speakers were rated by experienced teachers of Mandarin who maintained clear contrasts in nasal codas. Multiple regression analyses on acoustic measures and the perceptual rating indicated that extent of nasalization was the primary factor affecting native listeners' perception of the [n]-[ŋ] contrast.