Vietnamese is a tonal language, while German is a stress-timed one. A hypothesis based on this difference is that the Vietnamese săc2- and năng2-tone patterns may have an influence on the melodic performance of Vietnamese learners in German closed syllables. This study investigates the hypothesis by comparing the F0-contours in 15 closed syllables, each produced by 16 Vietnamese learners of German, with those produced by 10 native German speakers. Results show that the Vietnamese learners perform significantly different F0-contours from those of the German group. Further comparisons within the Vietnamese group between the F0-contours in the German syllables and the Vietnamese săc2- or năng2-tones, produced by the same learners, reveal striking similarities and thus, indicate a probable interference of these tone patterns. A discussion of the linguistic factors that motivate the Vietnamese learners to transfer these săc2- and năng2-tones suggests that the coda-tone-restriction in Vietnamese and the word stress in German play a crucial role in the melodic performance in closed syllables of Vietnamese learners.
