Previous studies reported that syllable-final nasals in Taiwan Mandarin, /n/ and /ŋ/, exhibit merging to different degrees in the vowel contexts of /i/ and /ə/ (e.g., Ing 1985, Kubler 1985, Hsu & Tse 2007, Fon et al., 2011). However, the discussion has been mainly on the merging directions, ethnic groups that display the mergers, and attitudes towards the different merging directions. Apart from the large evidence of merging from perceptual identification of the final nasal, this study employs ultrasound imaging technique to examine tongue postures of the syllable-final nasal following /i, a, ə/ vowel contexts. Preliminary results showed that /n/ and /ŋ/ were distinct both acoustically and articulatorily in the context of /a/, echoing earlier findings (e.g., Fon et al., 2011). On the other hand, while the contours of tongue shapes demonstrate extensive overlapping between /n/ and /ŋ/ following /i/ and /ə/, their correspondent acoustics display different degrees of nasalization on the preceding vowels (cf. Chen, 2000). More generally, the results suggest that the merging in syllable-final nasals undergoes an incomplete process and the acoustic contrasts might have lie in the nasalization of the preceding vowels and less so in syllable-final nasals.Previous studies reported that syllable-final nasals in Taiwan Mandarin, /n/ and /ŋ/, exhibit merging to different degrees in the vowel contexts of /i/ and /ə/ (e.g., Ing 1985, Kubler 1985, Hsu & Tse 2007, Fon et al., 2011). However, the discussion has been mainly on the merging directions, ethnic groups that display the mergers, and attitudes towards the different merging directions. Apart from the large evidence of merging from perceptual identification of the final nasal, this study employs ultrasound imaging technique to examine tongue postures of the syllable-final nasal following /i, a, ə/ vowel contexts. Preliminary results showed that /n/ and /ŋ/ were distinct both acoustically and articulatorily in the context of /a/, echoing earlier findings (e.g., Fon et al., 2011). On the other hand, while the contours of tongue shapes demonstrate extensive overlapping between /n/ and /ŋ/ following /i/ and /ə/, their correspondent acoustics display different degrees of nasalization on the preceding vowels (cf....