This paper disambiguates two linguistic factors in L2 English word stress acquisition. Chinese EFL learners have been found to prefer a syllable to be stressed when it is closed by a sonorant [5]. This non-English-like pattern is open to at least two interpretations: (a) an effect of L1 transfer, and (b) an effect of universal sonority-weight mapping. In order to evaluate the analyses, data was collected from L1 Vietnamese speakers whose native language allows both sonorant and obstruent codas. If the Vietnamese speakers do not show a preference for sonorant codas, then the L1 transfer interpretation is supported. If both groups acquire L2 English stress in a similar way, then an effect of phonological universal might be possible. These predictions are tested in a perceptual experiment. The results support the hypothesis that the L2 English stress pattern shown by L1 Chinese speakers is due to phonological universals.