John J. Ohala

Towards an articulatory phonology

We propose an approach to phonological representation based on describing an utterance as an organised pattern of overlapping articulatory gestures. Because movement is inherent in our definition of gestures, these gestural ‘constellations’ can account for both spatial and temporal properties of speech in a relatively simple way. At the same time, taken as phonological representations, such gestural analyses offer many of the same advantages provided by recent nonlinear phonological theories, and we give examples of how gestural analyses simplify the description of such ‘complex segments’ as /s/–stop clusters and prenasalised stops. Thus, gestural structures can be seen as providing a principled link between phonological and physical description.

The Origin of Sound Patterns in Vocal Tract Constraints

The ultimate task of phonology is to discover the causes of the behavior of speech sounds. To do this phonologists must refer to the way speech is created and used by humans, including how it is stored in the brain, retrieved, executed, perceived, and used to facilitate social interaction among humans. The domain of phonology is therefore mind, matter, and manners. This chapter is about matter: some aerodynamic and anatomical properties of the vocal tract and how they influence the shape and patterning of speech sounds. A secondary aim of this chapter is to show not only that the study of the physical aspects of speech assists phonology but also that phonology can return the favor: A careful, perhaps inspired, analysis of sound patterns in language can help us to discover and understand some of the complexities of speech production (Ohala, 1975a, 1975b, 1978a, 1978b, 1980, 1981; Ohala & Riordan, 1979; Shattuck-Hufnagel, Chapter 6, this volume; MacKay, 1972).

Production of Tone

Publisher Summary This chapter discusses the aspects of tone production that may be relevant to an understanding of tonal phenomena. It discusses laryngeal anatomy and physiology; reviews the controversial issues in tone production; and provides an introduction to the literature in this area. The larynx is a valve and a sound producer. As a valve, it regulates the flow of air into and out of the lungs and keeps food and drink out of the lungs. The two functions are accomplished by a relatively complex arrangement of cartilages, muscles, and other tissues. The hard structure of the larynx consists of four principal cartilages: the thyroid, the cricoid, and a pair of arytenoid cartilages. The thyroid and cricoid are connected and pivot about a transverse axis. The two arytenoid cartilages are connected to the cricoid cartilage via a ligamentous hinge and sit atop its rear rim. Each can rotate on the rim of the cricoid in such a way as to bring their front projections towards or away from the midline. The two vocal cords or, more appropriately, the vocal folds, are basically ligaments that stretch between the inner lower front surface of the thyroid cartilage and the front faces of the separate arytenoid cartilages. It is the rotation of the arytenoid cartilages that enables the vocal cords to be brought together toward the midline for voicing or breath-holding or to be separated from each other.

Prosodic phonology and phonetics

Our colleague Charles Fillmore invented the following parable (personal communication) to characterise the two dominant ways linguists attempt to solve problems of language structure and behaviour.

THE PHONETICS OF NASAL PHONOLOGY: THEOREMS AND DATA

Publisher Summary Physiologically a nasal speech sound is quite simple: it just involves lowering of the soft palate to a degree sufficient to couple the oral and nasal cavities acoustically. With a concomitant oral closure, a nasal consonant is produced; without it, a nasal vowel. This chapter discusses the extent to which sound patterns in language can be derived, such as theorems from first principles, the latter being facts that are empirically verifiable and pertinent as well to domains other than speech. The function of the speech mechanism may be considered the conversion of static or slowly varying air pressure into the rapid air pressure variations that are called sound. This task is accomplished by what is in effect an interconnected series of chambers whose volumes, and thus, also air pressures, may be varied by piston-like mechanisms and whose input and output of air flow are regulated by various valves.

Passive vocal tract enlargement during voiced stops

Voiced stops should become devoiced within 5 to 10 m of stop closure if there is no vocal tract enlargement to delay the inevitable reduction in transglottal pressure drop. Since stops may be voiced longer than this, some cavity expansion must take place, either passive through tissue compliance or active through larynx lowering and the like. To estimate the duration of voicing in stops when only passive enlargement occurs, subjects produced isolated nonsense words of the form VC:V, where V was one of a variety of English vowels and C: was an artificially prolonged /b/, /d/, or/g/. Oral air pressure was vented through a catheter leading from the pharynx to the atmosphere via the nasal cavity. At unpredictable times, a solenoid‐activated valve closed the catheter and the consequent build‐up of oral pressure extinguished the voicing. Voicing continued after this closure longer during /b/ than /d/ or /g/, and longer when coarticulated with high vowels than with low vowels. These results can most plausibly be...

Speed of Pitch Change

In an attempt to determine the response characteristics of the larynx in voluntary pitch change, five adult male subjects were instructed to execute a variety of continuous pitch changes, as rapidly as possible, within the range 90–220 Hz. For a given pitch interval, there was a marked tendency for all upward pitch change to take longer than a downward pitch change. Also, unexpectedly, there was no marked tendency for a change involving a wide pitch interval to take longer than a change involving. a smaller interval. Speculations on the physiological reasons for these relations, as well as their possible relevance to the phonology of tone and intonation, will be offered. [Supported by the National Science Foundation and a University of California Faculty Research Grant.]

Acoustic basis for universal constraints on sound sequences

A hypothesis is presented which predicts universal constraints on phoneme sequences (phonotactics) by reference to certain acoustic properties of these sequences. Two factors are hypothesized to influence these constraints. First, the magnitude of the trajectory of these soundsequences in a multidimensional acoustic space should be directly proportional to their perceptibility, and hence viability within a language. Second, the similarity of two or more such trajectories should determine the likelihood of their confusion and subsequent merger. (Unaccounted for in this analysis is unidirectional confusion and absence of soundsequences due to articulatory constraints.) The magnitude of, and distance between trajectories were computed for various sequences of initial consonant clusters and vowels. Results correctly predicted that such sequences as [bw‐], [‐wu], and [‐yi] are not as favored as [dw‐], [‐wa], [‐ya], and [‐yu]. Further, soundsequences such as [by‐] and [gw‐] were predicted to be confusable with [d‐] and lb‐l, respectively, which is in accord with known sound change processes.

Sound change as nature's speech perception experiment

Abstract Variation in pronunciation observed in speakers today parallels in many details the documented variation in pronunciation over the centuries (sound change). It is reasonable to conclude that there is some necessary link between the two. I argue that diachronic variation emerges for the most part from synchronic variation thus: universal and timeless physical constraints on speech production and perception leads listeners to misapprehend the speech signal. Any such misapprehension that leads the listener to pronounce things in a different way is potentially the beginning of a sound change. If we study sound change we can gain insights into how speech is produced and perceived. I exemplify this point by considering a variety of sound changes that involved voiceless fricatives: so-called spontaneous nasalization, s-aspiration, and nasal effacement. They suggest that one cue to this class of sounds is a special voice quality on that portion of vowels immediately abutting the fricative.

Respiratory Activity in Speech

Functionally the subglottal respiratory system behaves for the most part like a piston in a piston chamber driven with a constant force (the sum of thoracic and abdominal muscular forces plus the elastic recoil force). Small, short term, variations in subglottal air pressure occur nevertheless due to (a) short-term variations in the resistance to the exiting airflow, i.e., from glottal and supraglottal articulations and (b) the inertia of the pulmonic system which creates delays in its passive response to such short-term variations in subglottal pressure. This casts doubt on claims of active contribution of the pulmonic system in the implementation of syllables, stress, certain sentence-final fundamental frequency contours, and certain segment types, e.g., aspirated stops.