Thirty Korean, Chinese, Thai, American, and Spanish, subjects heard two-syllable Japanese words including geminate or single stops in two pitch accent contexts. The subjects discriminated between geminate and single stops. Their discrimination ability was examined and compared among these different speakers. Five language groups were clearly separated into two groups according to the results. The first group (Korean, Chinese, and Thai) that had three-way stop contrasts different in tense or aspiration, showed a lower correct ratio. Also pitch accent (LH, HL) and consonant type (/p/,/t/,/k/) of the stimuli appeared to influence the discrimination similarly in this group. The second American and Spanish group could perform the discrimination task better than the first group and little influence of accent and consonant contexts were observed. The second group seemed to depend more on the absolute closure duration of stop consonants in judging geminate or single. These results suggest that different language speakers use different acoustic cues in discriminating non-native contrast. In particular, while Japanese speakers discriminate single stops from their geminate counterparts using only relative segmental duration, Korean, Chinese, and Thai speakers seem to use additional acoustic information such as tense and aspiration.