1 Is vowel reduction centralization or contextual assimilation? Vowel reduction has traditionally been considered as centralization. A tube modelling a centralized connguration of an average sized male speaker resonates at 500 Hz, 1500 Hz, and 2500 Hz (Fant 1960). That is, the formants are evenly spaced. It was suggested that in both British and American varieties of English, most vowels approa...