Fricative vowels are unusual in languages worldwide. High Vowel Fricativization (HVF) is a model for the emergence of such sounds, which requires vowels to have consistent turbulence to generate wall noise source as the driving force. However, its phonetic foundation remains unclear. To investigate, 38 native speakers of Changzhou Chinese produced a series of CV monosyllabic words with alveolar fricative vowel /ʑ̩/ and its plain counterpart, high front vowel /i/ as the nucleus across five tones. We measured the spectrograms, Harmonics-to-Noise Ratio (HNR) and several phonation measurements for each token. Results show that the high vowel in lower register exhibits breathy phonation and HNR values similar to fricative vowels. It suggests that lower register /i/ is produced with audible turbulence, acting as one of the prerequisites for fricativization. Listeners may misperceive the vowel as a new sound category primarily cued by frication noise, eventually spreading the sound to other tonal categories and giving rise to a fricative vowel /ʑ̩/. Overall, this study provides the phonetic foundation for the emergence of frication noise in fricative vowels, arguing that register can be a motivation for change in the fricativization of high vowels.