Volume 28, Issue 2

In an attempt to describe the mechanical properties of lower lip movement during speech production, EMG activity from the orbicularis oris inferior and depressor labii inferior muscles was observed along with jaw-independent movement of the lower lip in the inferior-superior dimension. A simple analog computer was employed to aid in the determination of this EMG movement transfer function. The results of the analysis suggested that one predominant mechanical limitation on lower lip movement in the inferior-superior dimension is the viscosity of muscle contraction, which varies most directly with the rate of active muscle shortening. There was also evidence of an elastic component which acted, in part, as an energy storage element to return the lip to the closure position.

This report highlights general implications stemming from two studies of normal subjects’ articulation via dynamic palatography instrumentation. The Kydd-Belt palatal device was utilized in association, first, with cinematographic recording of a light palatal analog, then with a 12-channel multiple-event counting system; a 13th channel recorded the presence of laryngeal tone, while a 14th channel recorded time segments. Patterning of contacts, ‘approach’ patterns, seating, and release behavior, as well as attempts to associate contacts with laryngeal tone were examined. The results are discussed in terms of their general implications to the act of articulation, the behavior of the tongue apex and lateral borders, symmetry of contacts, and sequencing of linguapalatal contacts.

The Harary-Paper distributional calculus is further developed by establishing the probability distributions of distributional aggressivity, attractivity and symmetry of linguistic units and by deriving statistical procedures to evaluate their degree and differences. To minimize the effort of evaluating the differences, a table is given where one can find the results mechanically. The procedure is illustrated by phonological examples.

The author examined cineradiographic tracings of 92 syllables in Twi including examples of all five tense vowels, all five lax vowels, two nasalized vowels and six long vowels in order to determine (a) whether the feature ‘covered’ is needed at all, (b) if it is not needed, whether it is merely an alternate term for tense-lax, (c) if it is needed, to what articulatory configurations it refers and (d) whether it is, in any case, the best term available. He confirms that the tense set is characterized by a widening of the pharynx but notes that it is not the case that the five tense vowels as a set have wider pharynges than all the lax vowels as a set. This is not even true of the eight non-low vowels. He concludes that the most useful way of characterizing vowel harmony in Twi is to refer to tense-lax at the level of competence and to pharynx width at the level of articulatory configuration.