Volume 45, Issue 2-4

A fundamental problem in phonological theory is the fact that processes often operate on consistent subsets of the distinctive features within a segment, like the features that characterize place of articulation. Recent research has responded to this problem by proposing a hierarchical organization of the features into functionally related classes, grouped under nodes of a tree structure. This ‘geometry’ resembles earlier theories that accomplish the same thing with multivalued features. This article reviews and expands the evidence for feature geometry. Within the segment, it is argued, the major dichotomy is between a Laryngeal node and a Place node. The manners of articulation – sonority, consonantality, nasality, and continuance – inhere in the segment itself rather than any of its subsidiary parts. Within the Place node, the division is into major articulators, each with its own subordinate features. Evidence is drawn from processes of assimilation and debuccalization and from the assimilatory and dissimilatory effects of the Obligatory Contour Principle.

The purpose of the work described here was to relate different types of phonological categories – like phonemic distinctive features and syllable boundaries – with articulatory parameters for lip and jaw height. The analysis is based on data for 2 talkers of American English, using the University of Tokyo X-ray microbeam system. We studied the articulatory realization of linguistic contrasts in syllable boundary location for the intervocalic labial stop consonant /p/ and the articulatory realization of intervocalic /p/ in the environment of phonemically different vowels. The /p/s in contrasts associated with the phonemic vowel environment (e. g., /p/ in /ipi/ versus /apa/) were realized in articulation by a constant lip pellet position, implemented by an inverse relation between jaw height and lip articulator height. The syllable structure contrasts (e. g., syllable-initial /p/ versus syllable-final /p/) were realized by jaw height differences, without any lip articulator difference. These results can be accounted for by describing the observable lip pellet position for /p/ as a function of two independent variables: a constant lip pellet goal, at the level of segmental vowel environment, plus a jaw height for a particular syllable structure.

The vertical movement of a sample point of the velum surface in sentences uttered by 2 speakers of English has been investigated. The temporal patterns of velum movement were approximated with a series of rules. Our findings suggest (1) that the feature [ ± nasal] alone fails to explain velum height movement patterns; (2) that there are no target values for the velum for vowels (at least in the material under investigation), (3) that prosodic or configurational factors such as intrasyllabic position and stress patterns strongly influence velum height, the speed of velum movement, and the timing of velum gestures, and (4) that the strategies used by the 2 speakers are different with respect to control of movement velocity. We propose a suprasegmental feature [ ± strong] to account for observed movement patterns, including timing relations between velum raising and lowering gestures and articulatory gestures of consonantal articulators such as the lips and the tongue tip.

Two approaches to seeking stable patterns in the gestural organization of speech are examined: local organization (individual gestures coordinated with other individual gestures) and global organization (gestures forming larger conglomerates). Articulatory evidence from American English words with a variety of initial consonants and clusters shows that syllable-initial consonants form a global organization (indexed by a metric we term the C-center) that is coordinated with the syllable’s vowel gesture. For syllable-final consonants, however, the evidence suggests that a local organization is employed: The first postvocalic consonant gesture is coordinated with the vowel gesture. Implications of these different styles of organization for the perceptual and phonological structure of speech are discussed.

A number of different prosodic effects (e. g. intonation-phrase-final position, the presence of stress or accent) increase syllable duration, as conventionally measured by the spacing of abrupt energy transitions in the acoustic signal. However, different prosodic contrasts may have different influences on syllable-internal articulatory organization. The present study examined the time course of vowel-related opening and closing mandibular gestures in four different prosodic contexts. For some prosodic effects, such as intonation-phrase-final lengthening, longer acoustic durations were associated with a disproportionate lengthening of the latter part of the vocalic gesture. By contrast, the presence of nuclear stress was associated with a more even distribution of lengthening throughout the syllable. These results suggest that the rhythmic effects of different prosodic contrasts cannot be adequately modelled in terms of millisecond values or durational ratios for acoustic segments. It is proposed that a suitable phonological representation of the rhythms of stress and phrasing might describe them as the time course of a syllable’s phonetic sonority.

We provide a summary of our recent research on the control of rapid action sequences in speech production, emphasizing findings about the advance planning and hierarchical organization of such utterances. The effects of number of elements in the utterance (its ‘length’) and other factors on maximum production rates of short utterances lead us to infer that a ‘motor program’ for the whole utterance, prepared in advance, controls the execution of each of its ‘units’. Findings from studies of typewriting as well as speech production have led us to a model in which the performance of each unit is controlled by two processes arranged in sequence: one ( subprogram selection ) whose duration increases linearly with sequence length, and the other ( command ) whose duration depends on type of unit. Quantitative aspects of the production of utterances composed of different types of element suggest that the action unit in speech is the stress group or metrical foot. The virtual identity of the timing of word and nonword utterances implies that the utterance program is sufficiently detailed so it can be executed without reference to learned routines for words stored elsewhere in memory. We review our search for properties of performance that are suggested by the model: First, the time from a reaction signal to the first unit (the latency) increases linearly with utterance length. Second, the maximum length utterance controlled by one program depends on unit size. Third, the effect of utterance length on production timing is localized (intermittent), rather than affecting all parts of the articulatory stream. And fourth, the effect of utterance length on production timing appears in just one epoch per unit.