Intrinsic fundamental frequency (F0) in American English vowels is affected by regional variation

Abstract

There is a relationship between F0 values and vowel height: High vowels have higher F0 than low vowels. A long-standing debate has centered on whether this intrinsic F0 (IF0) pattern is an automatic consequence of vowel articulation or whether it represents deliberate effort to enhance vowel contrast. We provide new data from regional variation suggesting that IF0 is partly controlled by the speaker. F0 was analyzed in high, mid, and low vowels, stressed and unstressed, in 36 females representing dialects spoken in Ohio, Wisconsin, and North Carolina. A robust finding was that dialects differ in their use of IF0 in stressed vowels: IF0 differences between high and low vowels in North Carolina were significantly smaller than those in Ohio and Wisconsin for measurements at vowel onset, offset, peak F0, and overall F0. High vowels had higher IF0 than low vowels in all dialects, confirming the universal aspect of IF0. However, the magnitude of this difference was dialect-specific, which suggests a relative independence of IF0 from vowel height. The lack of correspondence between dialect-specific formant values and dialect-specific IF0 indicates that the quality of vowels and their IF0 value are two features that need to be learned separately.