Silverman, Daniel. (1997). Phasing and recoverability. Outstanding dissertations in linguistics series. New York: Garland Publishing. 242 pages.
Reviewed by Stefan Frisch, University of Michigan.
This book is a revised version of the author's 1995 UCLA dissertation. The primary thesis defended by Silverman is that auditory salience plays an important role in explaining the typology of phonological segment inventories. The relative phasing of laryngeal and supralaryngeal gestures is examined as a case study. Silverman demonstrates there is a typological preference for phasing patterns in which the gestures are optimally recoverable. Further, he proposes that sub-optimal patterns are only found in inventories where the optimal patterns are also present. (Note that Silverman does not crucially adopt the segment as a phonological primitive. He is concerned primarily with gestures and their realization in a system of syntagmatic contrasts. The terms 'segment' and 'segment inventory' are used only for expository convenience.)
Synopsis:
Chapter 1. Introduction
This chapter introduces the primary thesis: Cross-linguistically, laryngeal and supralaryngeal gestures are phased to make their values maximally auditorily salient. Silverman argues that parallel production of contrastive gestures is informationally optimal, but only if those gestures are auditorily recoverable. In cases where parallel production would make contrastive values unrecoverable, gestures are serially sequenced. For example, in aspirated stops, laryngeal abduction is sequences to follow the stop closure, resulting in broadband noise. If laryngeal abduction and stop closure were simultaneous, the state of the larynx would not be recoverable from the resulting acoustic signal (silence).
Silverman also introduces the 'gestural score' notation of Articulatory Phonology (Browman & Goldstein, 1986) used in the description of the gestural patterns. Each gestural score is accompanied by a set of temporally aligned descriptions of acoustic cues which highlight the importance of the recoverability of the gestures. The resulting segmental percept is also given, to highlight whether all of the contrastive segmental information has been effectively transmitted. Using this notation, he exemplifies the four logically possible phasing patterns: parallel, sequenced, expanded, or truncated. In the parallel phasing pattern, two gestures are phased to be fully simultaneous. In the sequenced pattern, two gestures are serially ordered. In the expanded pattern, one gesture both begins before and ends after another. In the truncated pattern, one gesture is phased to be simultaneous with a portion (beginning or end) of another gesture.
Chapter 2. Previous work
In this chapter, Silverman reviews previous research on articulatory timing, auditory response to acoustic signals, and the relevance of auditory contrastiveness to segmental inventories. Two results are of particular importance. First, a combination of auditory factors favor patterns where low intensity signals are followed by high intensity signals. Second, languages employ contrasts which are maximally auditorily distinct.
Chapter 3. Obstruents and laryngeal gestures
This chapter contains typological evidence to support Silverman's thesis. Cross-linguistically, laryngeal gestures of abduction or constriction are overwhelmingly phased to follow supralaryngeal constriction, which maximizes the recoverability of both gestures. The sub-optimal pattern, where the laryngeal gesture precedes the stop release is found only when the optimal pattern is also present. For obstruents, which have a minimum of acoustic energy to work with, these are the only two phasing patterns.
Chapter 4. Sonorants and laryngeal gestures
Sonorants have a greater amount of acoustic energy, and so laryngeal gestures can overlap with supralaryngeal gestures. The most attested pattern, for languages which do have a laryngeal contrast for sonorants, is for the laryngeal gesture to be truncated to the beginning portion of the supralaryngeal gesture. Parallel to the obstruent case, this phasing pattern puts the low-energy breathy or glottalized portion of the sonorant before the high-energy modally-voiced portion, maximizing auditory salience. Again, the less optimal pattern truncates the laryngeal gesture to the latter portion of the supralaryngeal gesture. Ordinarily, the laryngeal and supralaryngeal gestures are not completely overlapped, as contrastive supralaryngeal gestures (such as nasal place of articulation, for example) would be rendered non- recoverable. However, an interesting special case is found in laterals. Due to the formant structure of laterals, languages generally do not have contrasts in their place of articulation. Thus, in some cases (e.g. Zulu), contrastive laryngeal gestures are realized fully parallel with the supralaryngeal gesture. A similar pattern is found for coda nasals in Comaltapec Chinantec, where the place of articulation is contextually determined. In contrast to onset nasals, which have contrastive place of articulation, laryngeal abduction is realized in parallel with the supralaryngeal gesture in coda nasals and no contrasts are lost.
Chapter 5. Vowels and laryngeal gestures
In this chapter, vowels with contrastive laryngeal gestures are discussed. Silverman claims that, since vowels have an abundance of acoustic energy, laryngeal gestures can be implemented in parallel with supralaryngeal gestures without loss of auditory contrast. However, this pattern is auditorily the least optimal. Like the sonorant case, the optimal pattern is for the laryngeal gesture to be truncated to the beginning portion of the vowel, resulting in ?V or hV sequences. Less optimal is the opposite phasing pattern, resulting in V? or Vh. Typologically hV is indeed much more prevalent than voiceless vowels or Vh (and similarly for laryngeal constriction).
The bulk of the chapter (and the book) is devoted to 'laryngeally complex' vowels in the Otomanguean languages. The term larygeally complex is used for vowels which realize both contrastive phonation (breathy or creaky) and tone. One example, Comaltapec Chinantec, has eight vowel qualities with five tonal qualities and two voice qualities. In addition, this language has nasalization and a length contrast which leads to 320 possible realizations of the nucleus. Not surprisingly, words in this language are generally monosyllabic, and nucleus quality is used to differentiate many of the lexical contrasts.
Silverman argues that simultaneous realization of breathiness/creakiness and tone would render the tone contrasts unrecoverable. The cross-linguistically prevalent pattern is for the laryngeal contrast to be truncated to the beginning of the vowel, which is auditorily optimal. The tone is then saliently realized during modal phonation in the latter portion of the vowel. The opposite sequencing, with the laryngeal after the tonal contrast (and modal phonation) is also attested. Silverman finds only two cases where tonal and laryngeal contrasts are executed simultaneously (the Tibeto-Burman languages Mpi and Tamang). In one of those cases, there are only two tones, so tonal contrasts may not be in as much danger, as the tones would be more distinct than in the case of Comaltapec Chinantec, with eight tones.
Critical evaluation:
Overall, this is an inspirational volume demonstrating the importance of auditory/phonetic explanation for phonological patterning. It is one of the first of a series of UCLA dissertations on this topic, which together address a wide range of phonological phenomena. Silverman's analysis bridges the phonetics/phonology gap in a number of ways. For example, an arbitrary number of phasing differences, which might be dismissed as 'phonetic implementation', are shown to be reducible to a small set that can be phonologically contrastive. This reduction, via the more abstract temporal relationships of simultaneity and precedence, nicely complements work in speech perception on the cross-linguistic (and cross-species) robustness of the categorical perception of voice onset time continua (Kuhl & Miller, 1975; Pisoni, 1977).
To its credit, this book contains over a dozen reasonably detailed case studies on the realization of laryngeal contrasts in different languages. In many cases, recordings were available so the presence of the phasing relationships were verified, and spectrograms of appropriate examples are given. These case studies often address potential counterexamples to Silverman's typological claims. For example, the Mon-Khmer language Chong possesses coda stops with contrastive creakiness, but creakiness is realized only in the non-optimal way as a pre-glottalized stop. In the Chong case, however, other aspects of the morphophonology require the non-optimal realization to avoid loss of contrast. In particular, coda stops are obligatorily unreleased, and the language is non-suffixing. Due to these additional constraints, post-glottalized phasing would not saliently encode the larygneal contrast. This type of constraint interaction is quite compatible with the general approach of Optimality Theory (Prince & Smolensky, 1993), and in fact the original version of this dissertation presented constraint tableau in such cases. The proposed constraints are quite broad and were informally described, so the Optimality Theoretic analysis did not add to the exposition, and the book reads more easily without it.
Despite the lack of a formalist analysis, this book raises a number of issues which are relevant to current formal concerns. In the Otomanguean language Copala Trique there are different phasing relationships between vocalic and laryngeal gestures. The laryngeal gestures (breathiness and creakiness) can be truncated to the first portion of the vowel, the second portion of the vowel, or can 'interrupt' the vowel, appearing in the middle. These three locations for a laryngeal gesture support lexical contrasts, and there is clear evidence that the interrupted vowels are monosyllabic. Encoding these three configurations using more abstract representations than Articulatory Phonology is no trivial task. In addition, the correspondence theory approach to faithfulness considers segmentally aligned and ordered input and output (McCarthy & Prince, 1995). The presence of relatively small but contrastive differences in phasing require subsegmental correspondence relations between the input and output. Another missing aspect of an Optimality Theoretic analysis would be a factorial typology of constraint interactions. While Silverman's coverage is quite extensive, I would be interested in seeing a discussion of the pros and cons for each logical possibility in phasing between laryngeal and supralaryngeal gestures. Such a discussion will eventually be needed in order to determine whether the Silverman's proposal is is truly predictive, or just informally defined to the extent that any observed pattern could be explained.
In a few instances, Silverman makes use of the UPSID database of segmental inventories (Maddieson, 1986) to demonstrate that the typological predictions are satisfied. Unfortunately, quantitative differences are not reported in most cases. While sufficient data may not be available, a quantitative analysis is desirable in order to address a current question in work on phonetic explanation for phonological patterns: Are non-optimal patterns avoided to the degree that they are non-optimal? In other words, is the hypothesized functional force of auditory recoverability transparently reflected in the patterns within and across languages, or is it 'phonologized' in some way by the language learner such that there is no quantitative relationship? The answer to this question has implications for the architecture of the phonetically grounded grammar, as quantitative constraints or quantitative constraint rankings would be required.
This book touches on a number of other very important issues that should be topics of ongoing research. The central role of the recoverability of contrasts leads inevitably to the question: What is a contrast? Assuming the psychological reality of the segment provides a simple answer, but one which is not entirely correct. The three contrastive phasing relationships in Copala Trique are not amenable to a segmental analysis. In Chong, a combination of coda unrelease and lack of suffixation is claimed to lead to pre-glottalized stops. This case is contrasted with Korean, where there is some suffixation, and post-glottalized stops are maintained in that environment but neutralized elsewhere. I wonder how frequent the neutralizing environment must be before a non-optimal pattern becomes necessary or the contrast is lost? Why isn't the laryngeal gesture phased before the stop closure in the neutralizing environment, but after in the non-neutralizing environment? Perhaps some other constraint is involved here.
In many of the case studies given, the simple syllable structure and monosyllabic tendencies of the languages are mentioned as reasons why complex and non-optimal phasing relations are found at all (in most cases, the optimal recoverability of supralaryngeal gestures is found if contrastive laryngeal gestures are not used at all). This suggests that there is some minimal set of contrasts required to create a sufficient number of open class items for a language to be a useful communication system, and that differences in syllable structure, word length, and segmental inventory size interact in some fashion to this end. The answers to these deeper questions appear to be closer to our understanding when the phonological system is conceptualized as implied in this book, as a combinatorial system of articulatory/acoustic contrasts highly constrained by a variety of functional factors.
References:
Browman, C. P. & Goldstein, L. (1986). Towards an articulatory phonology. Phonology yearbook 3: 219-252.
Kuhl, P. K. & Miller, J. D. (1975). Speech perception by the chinchilla: Voiced-voiceless distinction in alveolar plosive consonants. Science 190: 69-72.
McCarthy, J. J. & Prince, A. (1995). Faithfulness and reduplicative identity. Papers in optimality theory. University of Massachusetts occasional papers 18. Amherst, MA: GLSA. pp. 249-384.
Pisoni, D. B. (1977). Identification and discrimination of the relative onset time of two component tones: Implications for voicing perception in stops. Journal of the Acoustical Society of America 61: 1352-1361.
Prince, A. & Smolensky, P. (1993). Optimality theory: Constraint interaction in generative phonology. Rutgers University Center for Cognitive Science technical reports 2. New Brunswick, NJ: RUCCS.
Reviewer: Stefan Frisch, Language Learning Visiting Research Assistant Professor, Program in Linguistics, University of Michigan. Ph.D., Northwestern University, 1996. Research interests include phonetics, phonology, psycholinguistics, and computational linguistics.
Reviewer's address: Stefan Frisch Program in Linguistics University of Michigan 1076 Frieze Building 105 S. State St. Ann Arbor, MI 48109-1285
[email protected] http://www-personal.umich.edu/~sfrisch
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