A note on "Information conveyed by vowels"

In an early experiment using synthetic speech, it was shown that raising or lowering the formants in an introductory sentence affected the identification of the vowel in a following test word [P. Ladefoged and D. Broadbent, J. Acoust. Soc. Am. 29, 98-104 (1957)]. This experiment has now been replicated using natural speech produced by a phonetician using two different overall settings of the vocal tract.