Disassociating the effects of age from phonetic change
Our study aimed at disassociating age-related from phonetic changes in broadcasts by British-American radio commentator Alistair Cooke, spanning 60 years. Both the first formant (F1) and fundamental frequency (f0) in non-low vowels showed a falling-rising pattern with increasing age. We argue that this covariation may have a perceptual origin because the distance between F1 and f0 is a perceptual cue to vowel height. A covariation of F1 and F2 in low back vowels is also consistent with a perceptual explanation. By contrast, F1 changes in low vowels may be associated with physiological changes to the jaw-opening mechanisms. Finally, we discuss phonetic changes, showing accent reversion from General American towards Cooke’s former Received Pronunciation over a thirty-year period.