Viii. Speech Communication Academic and Research Staff A. Physiology of Speech Production: a Preliminary Study of Two Suggested Revisions of the Features Specifying Vowels

The feature 'tense' (as applied to vowels) has been widely discussed (cf. Chomsky and Halle,1 Jakobson and Halle, 2 and Stewart3), particularly with respect to its articulatory correlates and relationship to vowel duration. Motivated apparently by persistent questions about the articulatory correlates of 'tense' and certain acoustic considerations, Halle and Stevens4 have suggested a revision of the feature specification of vowels in which 'tense' is replaced by 'advanced tongue root.' They hypothesize that the features 'tense-lax' (which accounts for the oppositions /i-/, /u-U/ and others in English) and 'covered-uncovered' (which applies to vowel harmony in West African languages) "have in common one and the same phonetic mechanism and should, therefore, be regarded as a single feature in the phonetic framework." Their suggestion of the feature 'advanced tongue root' is based on a study of vowel harmony in Asante Twi by Stewart 3 in which he observes that the vowels /I, 6, a, 3, U/ (unraised) are "raised" to /i, e, 3, o, u/ by advancing the root of the tongue. Halle and Stevens4 support their argument with the tracings of the vowel pairs /iT/ and /u-U/ from one speaker of English in which it is obvious that for /i/ and /u/, the tongue root is drawn relatively forward, thereby causing an enlargement of the lower pharynx and a raising of the tongue body in the oral cavity. Their acoustic analysis shows that this gesture would cause the changes in FI and F 2 for front and back vowels that are commonly observed. They also argue that the gesture of advancing the tongue