A problem frequently encountered in studies of syllable boundary placement is that of inconsistency, that is, variation in subject responses when syllabifying given consonant clusters. In this empirical study we examine the degree and range of this variation, and the impact of pre-and post consonant cluster vowels on syllable boundary placement. Analysis showed high levels of syllable boundary variation between different cluster types, as well as a marked difference in the perception of syllable onsets and offsets. Syllable boundary movement due to the contextual of vowels was also found, due to both vowel type and aperture. We believe that these results point to a wider approach to syllabification than that traditionally held, involving interactions between vowels and the consonant cluster in the process of syllable onset detection.