This study investigated how the various rating groups with different mother tongues judge the fluency for the L2 speaking. It was expected that the Korean raters have different rating patterns from native English raters for Korean speaking of English. Fourteen raters took part in fifteen speaking samples. After L2 subjects` speech was assessed by two different rating groups, acoustic measurement of L2 speech was analyzed. The results show that the effect of raters` L1 background language exhibits differently in rating the L2 fluency. More specifically, Korean raters put more focus on pause duration in the fluency evaluation, while native English raters focused on speech rate. It means that their rating patterns could be different depending on the raters` background language.