https://www.selleckchem.com/pr....oducts/caerulein.htm
Regional variation in American English speech is often described in terms of shifts, indicating which vowel sounds are converging or diverging. In the U.S. South, the Southern vowel shift (SVS) and African American vowel shift (AAVS) affect not only vowels' relative positions but also their formant dynamics. Static characterizations of shifting, with a single pair of first and second formant values taken near vowels' midpoint, fail to capture this vowel-inherent spectral change, which can indicate dialect-specific diphthongization or