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Several factors can influence early prominence in double-stressed words (e.g., Maltese), namely the presence of foot-level stress clash with a following word, and their adjacency to domain-initial boundaries. We test whether initial accent can occur in such words even when the words are spoken in isolation. Fourteen targets and 26 tri-syllabic filler-items were produced in isolation and in a frame sentence, e.g., [Say Maltese again], by 12 English speakers. In isolation, ‘Early’ prominence on, e.g., Mal- is more likely because the target is utterance- and phrase-initial. In the Embedded condition, phrasal prominence should be less likely on the initial syllable because there is a weaker boundary preceding the target. Three linguists coded prominence location. Early prominence rates, and Early scores (sum of ‘Early’ judgements/token) were calculated. While 96% of the Embedded tokens were perceived with ‘Late’ prominence, this pattern appeared in only 48% of the Isolated targets. The Early scoreswere also significantly higher in the Isolated condition. Overall, results suggest that doubly-stressed words show stress shifting to demarcate the left IP-edge. Because this study uses contexts free of stress clash with a following word, its results provide evidence that other factors, namely domain-onset-marking, can influence prominence location.

It has been hypothesized that morphologically-complex words are mentally stored in a decomposed form, often requiring online composition during processing. Morphologically-simple words can only be stored as a whole. The way a word is stored and retrieved is thought to influence its realization during speech production, so that when retrieval requires less time, the articulatory plan is executed faster. Faster articulatory execution could result in more coarticulation. Accordingly, we hypothesized that morphologically-simple words might be produced with more coarticulation than apparently homophonous morphologically-complex words, because the retrieval of monomorphemic forms is direct, in contrast to morphologically-complex ones, which might need to be composed online into full word forms. Using Ultrasound Tongue Imaging, we tested this hypothesis with nine speakers of Scottish English. Over two days of training, participants learned phonemically identical monomorphemic and morphologically-complex nonce words, while on the third consecutive testing day, they produced them in two prosodic contexts. Two types of articulatory analyses revealed no systematic differences in coarticulation between monomorphemic and morphologically-complex items, yet a few speakers did idiosyncratically produce some morphological effects on articulation. Our work contributes to our understanding of how morphologically complex words are stored and processed during speech production.

This chapter reviews the acoustic correlates and perceptual cues of linguistic stress at the word and sentence level, mainly in English and other Germanic languages. A first theme is whether word and sentence stress can be ordered monotonically along the same phonetic scale, rather than involving different acoustic parameters and perceptual dimensions. Other topics are the phonetic reflexes of the Alternation Principle (‘NoClash’) and of changes in information structure as well as the effect of sentence stress on the temporal organization of words and phrases. The work on non-Germanic languages raises the issue of the weighting of stress correlates and its possible interaction with language-specific structure. Two hypotheses are evaluated: (i) languages will mark the difference between stressed and unstressed syllables more forcefully as word stress location is less predictable and (ii) a stress correlate will be less important if it is involved elsewhere in the phonology of the language.

This chapter presents the outline of a model of speech-production planning, based on symbolic phonology and the specification of surface-timing patterns using general-purpose timekeeping mechanisms. This phonology-extrinsic-timing-based, three-component (XT/3C) model includes a Phonological Planning Component, to set and prioritize the goals for an utterance; a Phonetic Planning Component, to quantitatively specify the acoustic targets and the movements to achieve them; and a Motor-Sensory Implementation component, to track the planned movements and adjust them to ensure that the targets are reached on time. This approach addresses some of the gaps in earlier speech-production models based on abstract symbolic phonology, by proposing a mechanism for the specification of context-appropriate surface phonetic variation, including timing. In this way it provides an alternative to the Task-Dynamics-based approach embodied in Articulatory Phonology.

This chapter summarizes the basic mechanisms of the Articulatory Phonology model, currently the most thoroughly worked-out model in the literature, with a focus on its system-intrinsic mechanisms used to account for systematic variation in speech timing. Key features of the model are reviewed, and oscillator-based mechanisms are described for timing control for articulatory gestures, control of inter-gestural coordination, prosodic timing control, and the control of overall speech rate. Strengths of the AP/TD approach are discussed, which include facts that are well-accounted-for within this model, such as the predominance of CV syllables within the world’s languages, as well as characteristics of processing within the model that are assumed to be advantageous, such as the avoidance of the need to explicitly plan the details of articulatory movement when planning an utterance. This presentation forms the basis of the evaluation presented in subsequent chapters.

This chapter addresses the nature of the general-purpose timekeeping mechanisms that are assumed in phonology-extrinsic-timing models of speech production. The first part of the chapter discusses some current questions about the nature of these mechanisms. The second part of the chapter presents Lee’s General Tau theory (Lee 1998, 2009), a theory of the temporal guidance of action in voluntary movement. This theory provides a crucial component for our phonology-extrinsic-timing-based, three-component model of speech production because its tau-coupling mechanism provides a way to plan movements with appropriate velocity profiles, as well as endpoint-based movement coordination. In doing so, it provides a general-purpose, phonology-extrinsic alternative to AP/TD’s use of oscillators for the control of the time-course of articulatory movement and coordination.

This chapter presents evidence that challenges models in which phonological representations are temporal in nature, and where timing mechanisms are phonology-specific and intrinsic to the phonology. For example, evidence for separate representations of 1) movement targets vs. other parts of movement, and 2) spatial vs. temporal aspects, is difficult to account for in phonology-intrinsic timing approaches, where all parts of movement are determined by the same, spatiotemporal phonological representation. In the AP/TD phonology-intrinsic-timing approach, surface time is not represented, specified, or tracked, but instead emerges from the phonological system. Evidence that speakers do in fact represent surface time motivates the consideration of a phonology-extrinsic-timing-based approach. This evidence comes from actors’ interactions with perceived events, and also from speech: 1) constraints on the amounts of structure-related lengthening to maintain phonological length contrasts in quantity languages, and 2) different articulatory strategies for producing a given duration pattern. Finally, evidence for general-purpose timekeeping mechanisms in speech and non-speech movements is discussed.

This chapter introduces a theoretical framework, Optimal Control Theory, which will enable a phonology-extrinsic-timing-based, three-component model to determine values of controlled variables, and to model the influence of multiple factors on these parameter values. Key features of Optimal Control Theory models are discussed, as well as evidence for types of movement costs (including the cost of time) used in the models, and predictions of the models for the coordination of multiple effectors and hierarchical control. Finally, the chapter reviews Optimal Control Theory models currently used to account for timing phenomena in speech.

Effects of prosodic structure on surface phonetics are modeled in AP/TD in two ways: 1) via a set of PI and MuT adjustment mechanisms used to model lengthening effects at boundaries and on prominent syllables, and 2) via a hierarchy of coupled syllable, cross-word foot, and phrase oscillators, used to model poly-subconstituent shortening effects, and to control overall speech rate. These mechanisms are challenged by 1) findings presented in previous chapters that suggest that longer durations associated with boundaries and prominences are due to longer surface duration specifications, 2) findings presented here that show that polysyllabic shortening does not affect all words in an utterance, inconsistent with an oscillator-based mechanism that controls all aspects of any produced utterance, and 3) findings relating to speech rate presented in previous chapters which suggest that speech rate specifications relate to surface durations, rather than to planning oscillator frequencies. Patterns of speech timing presented in this chapter thus suggest that there are reasons to be uncertain whether periodicity is a major factor in speech motor control in typical speaking circumstances, and therefore call into question the use of suprasegmental oscillators.

This chapter begins to motivate the development of an alternative approach to speech production by pointing out three potential difficulties with the highly-successful Articulatory Phonology/Task Dynamics approach. First, it discusses the extensive nature of modifications to AP/TD default specifications required to account for the wide variety of surface phonetic forms. The need for a large number of adjustments in AP/TD raises questions about the appropriateness of the AP/TD default-adjustment approach, which would have been more appropriate if the default, non-prominent, phrase-medial, normal-speech-rate specifications could be used most of the time. Second, it discusses the lack of a principled explanation for behaviors described by Fitts’ law. While the theory can accommodate some aspects of Fitts’ law, others are not explained or accommodated. Finally, it suggests that AP/TD’s gestural score architecture raises the risk of spatial interference among overlapping, independent gestures. These three challenges taken together set the stage for the discussion of additional challenges in Chapter 4, which further motivate consideration of phonology-extrinsic-timing-based approaches to speech motor control.

Evidence presented in previous chapters suggests consideration of an alternative to the coupled-oscillator approach to modeling human speech planning and production processes. One alternative approach is based on the symbolic phonemic representations of Generative Phonology. This approach requires a separate mechanism to translate these symbolic representations into the quantitative context-appropriate specifications that can produce the surface form of an utterance. To date models of this type have not included comprehensive versions of components that complete this symbol-to-quantification translation process. This chapter reviews the evidence that supports a three-component model of this process, with an abstract symbolic Phonological Planning Component to specify the goals of the utterance at the level of contrastive feature cues; a Phonetic Planning Component to translate these goals into acoustic targets with their articulatory realizations; and a Motor-Sensory Implementation Component to track and adjust the articulatory movements which create the vocal-tract configurations that realize these goals. Development of such a three-component model would allow direct comparison with performance of the oscillator-based AP/TD model.

This is a book about the architecture of the speech-production planning process and speech motor control. It is written in reaction to a debate in the literature about the nature of phonological representations, which are proposed to be spatiotemporal by some, and symbolic (atemporal) by others. Making this choice about the nature of phonological representation has several fundamental implications for the architecture of the speech-production planning system, notably with regard to the number of planning components and the type of timing mechanisms. In systems with symbolic phonological representations, a separate phonetic planning component is required for speakers to plan the details of surface timing and spatial characteristics for each context. In contrast, the Articulatory Phonology system, which proposes spatiotemporal phonological representations, has a very different architecture, with fewer components. These contrasting assumptions about the spatiotemporal vs. symbolic nature of phonological representations have important consequences for how these two approaches deal with timing issues. This is because time is intrinsic to phonological representations in Articulatory Phonology, but is not part of symbolic phonology. These two proposals are evaluated in light of existing literature on speech and non-speech timing behavior. Evidence that challenges the Articulatory Phonology model inspired a sketch of a new model of the production process, based on symbolic phonological representations and a separate phonetic planning component to specify surface-timing details. This approach provides an appropriate account of what is known about motor timing in general and speech timing in particular. Keywords

This volume compares two very different approaches to modeling speech planning: Articulatory Phonology, with quantitative phonological representations and a set of phonology-intrinsic timing mechanisms, and XT/3C, an alternative model with non-quantitative symbolic phonological representations and general-purpose phonology-extrinsic timing mechanisms. It argues that the motor-control literature for both speech and non-speech supports the XT/3C approach, which expands on earlier models based on Generative Phonology to include a Phonological Planning Component to set the symbolic goals for an utterance, a separate Phonetic Planning Component to provide the quantitative target specifications for the utterance, and a Motor-Sensory Implementation Component to track and adjust the movements required to reach those targets on time. It preserves the insights of a symbol-based phonology, while also providing a comprehensive account of systematic phonetic variation, including timing.

This chapter summarizes the ideas that led to this book. Articulatory Phonology in the Task Dynamic framework (AP/TD) takes a very different approach from traditional Symbolic Phonology. That is, phonological representations in AP/TD are spatiotemporal, whereas a model developed from generative phonology has symbolic, atemporal phonology. This difference in phonological representation has significant implications for the architecture of the production planning process, which must account for the quantitative details of surface phonetic form. Findings in the literature on general motor timing and particularly on speech motor timing suggest that it is time to re-evaluate these two approaches. These findings motivate the development of a symbol-based, three-component model with separate phonological and phonetic planning components, as well as a motor–sensory implementation component, all guided by general purpose timekeeping mechanisms that are extrinsic to the phonology.

We demonstrate the workability of an experimental facility that is geared towards the acquisition of articulatory data from a variety of speech styles common in language use, by means of two synchronized electromagnetic articulography (EMA) devices. This approach synthesizes the advantages of real dialogue settings for speech research with a detailed description of the physiological reality of speech production. We describe the facility's method for acquiring synchronized audio streams of two speakers and the system that enables communication among control room technicians, experimenters and participants. Further, we demonstrate the feasibility of the approach by evaluating problems inherent to this specific setup: The first problem is the accuracy of temporal synchronization of the two EMA machines, the second is the severity of electromagnetic interference between the two machines. Our results suggest that the synchronization method used yields an accuracy of approximately 1 ms. Electromagnetic interference was derived from the complex-valued signal amplitudes. This dependent variable was analyzed as a function of the recording status – i.e. on/off – of the interfering machine's transmitters. The intermachine distance was varied between 1 m and 8.5 m. Results suggest that a distance of approximately 6.5 m is appropriate to achieve data quality comparable to that of single speaker recordings.

This study investigated interactions between vowel quantity and two types of prosodic lengthening (accentual lengthening and the combined effect of accentual and utterance-final lengthening) in disyllabic words in Northern Finnish. Two quantity-related constraints were observed. First, in both types of prosodic lengthening, vowels were lengthened less when they were next to a syllable containing a double vowel than when they were next to a syllable containing a single vowel (a quantity neighbour constraint). Second, a durational ceiling effect was observed for the phonologically single, half-long vowel under the combined effect of accentual and utterance-final lengthening. These findings can be seen to support the view that quantity languages regulate the non-phonemic use of duration because of the high functional load of duration at the phonemic level. Additionally, the combined effect of accentual and utterance-final lengthening appeared to have its own lengthening profile, distinct from the simple sum of the two lengthening effects suggested previously. Implications for speech timing research will be discussed.

Previous work on English disyllabic and trisyllabic words cannot distinguish two types of views on accentual lengthening: (1) phrasal accent affects a single, multisyllabic domain (the entire word), vs. (2) phrasal accent affects multiple, potentially separate, domains (e.g., the primary stressed syllable and the final syllable). In the present paper, we distinguish these views by examining the effect of phrasal accent on the durational patterns of English four-syllable words. We studied words of three types, with different positions of primary and secondary lexical stress: pattern 1000 (e.g. ˈ presidency ), pattern 2010 (e.g. ˌdemoˈcratic ), and pattern 1020 (e.g. ˈsuffoˌ cating ). Our results show that accent-related lengthening can affect multiple, potentially distinct, sites: the primary-stressed syllable, the secondary-stressed syllable rhyme (if the word has secondary stress), the onset of the word-initial syllable, and the final syllable. In addition, lengthening can “spill over” from a primary-stressed syllable onto a following unstressed syllable. Patterns of accent-related lengthening on onsets vs. rhymes are qualitatively different for stressed vs. word-edge sites, suggesting separate lengthening mechanisms.

The polysyllabic shortening hypothesis holds that the duration of a primary stressed syllable is inversely proportional to the number of additional syllables within the word. We examine the evidence for this process in British English speech by measuring the duration of primary stressed syllables in monosyllabic, disyllabic and trisyllabic words, both right-headed series – e.g. mend , commend , recommend – and left-headed series – e.g. mace , mason , masonry . In contrast with some of the original studies of polysyllabic shortening (e.g. Lehiste, 1972 ), we record target words both when carrying nuclear pitch accent and when unaccented. As in previous studies, we find strong evidence of polysyllabic shortening in accented words, an effect of comparable magnitude in right-headed and left-headed words. In unaccented words, polysyllabic shortening is minimal or absent, but there is evidence, supporting previous studies, of domain-edge effects localised to specific sub-syllabic constituents. Unlike these effects, which occur on both pitch-accented and unaccented words, polysyllabic shortening of the primary stressed syllable in these data is confined to pitch-accented words.

Following van Heuven and Sluijter (1996), this paper suggests that the tradition of equating prosody with variations in fundamental frequency (F0), duration and intensity may have originated from a tendency to view prosody as the music of speech. This paper discusses several problems with this musical view and suggests that a functional perspective may be more appropriate. The four functions include signalling (1) lexical contrast (as in e.g., lexical tone and quantity languages), (2) postural settings such as overall rate of speech, F0 height and span, (3) non-lexical meaning (e.g., surprise), and (4) prosodic structure. As motivated elsewhere, prosodic phonology accomplishes the third and fourth functions, where prosodic structure includes prosodic constituent and prominence hierarchies. Intonational events such as pitch accents and boundary tones align with respect to these structures. Correlates of prosodic structure include, but are by no means limited to, F0, duration, and intensity. It is hypothesi...

Utterance-final lengthening in Northern Finnish was investigated using tightly controlled laboratory materials, with particular focus on its interaction with the language's single (short) vs. double (long) vowel distinction. Like many other languages, Finnish exhibited utterance-final lengthening, although the estimates of magnitudes of lengthening on final vowels varied greatly depending on the treatment of the utterance-final breathy/voiceless portion of the vowel. As has been also shown for other languages, the lengthening occurred as early as the stressed, penultimate syllable of disyllabic words and was generally progressive. Crucially, vowel quantity interacted with the lengthening in a manner consistent with a hypothesis that Finnish regulates utterance-final lengthening to preserve its quantity system. Specifically, the voiced portion (the portion that is relevant to the perception of vowel quantity) of the longest single vowel (the half-long vowel) was restricted. Additionally, double vowels were lengthened less when the vowel in an adjacent syllable was also double, suggesting syntagmatic constraints. Our results support the view that utterance-final lengthening is a universal tendency but is implemented in language-specific ways and must be learned.

Boundary-related lengthening has been shown to affect the phrase-final word in a number of languages, but its precise distribution within the final word has not been determined. Some evidence suggests that it can begin before the final syllable (e.g. in an earlier main-stress syllable), and that it may be progressive (e.g. may affect the coda of the final syllable more than the nucleus and the nucleus more than the onset). However, only a small number of word shapes have been examined in any one language, so the available facts under-determine models of the duration adjustment process. A survey of final lengthening in words with various stress patterns in American English, using acoustic measures, shows that, in the conditions of these experiments, (a) although most of the duration increase occurs in the phrase-final syllable rime, statistically significant lengthening of 7–18% also occurs in the main-stress syllable rime, when the main stress syllable is not the final syllable, (b) this pattern is seen in both pitch-accented and unaccented final words, suggesting that it is not the result of nuclear-accent-related lengthening, (c) the distribution of lengthening across the syllables of the final word is not straightforward, in the sense that regions between the main-stress rime and the final rime appear to be skipped or lengthened less than the regions before and after them. These results suggest that the mechanism of boundary-related lengthening is more complex than current models propose; in particular, its distribution cannot be explained without reference to the location of main lexical stress and appears to involve more than one stretch of speech, at least in American English.

In the first part of the paper, we summarize the linguistic factors that shape speech timing patterns, including the prosodic structures which govern them, and suggest that speech timing patterns are used to aid utterance recognition. In the spirit of optimal control theory, we propose that recognition requirements are balanced against requirements such as rate of speech and style, as well as movement costs, to yield (near-)optimal planned surface timing patterns; additional factors may influence the implementation of that plan. In the second part of the paper, we discuss theories of timing control in models of speech production and motor control. We present three types of evidence that support models of speech production that involve extrinsic timing. These include (i) increasing variability with increases in interval duration, (ii) evidence that speakers refer to and plan surface durations, and (iii) independent timing of movement onsets and offsets.

This paper explores two related factors which influence variation in duration, prosodic structure and redundancy in spontaneous speech. We argue that the constraint of producing robust communication while efficiently expending articulatory effort leads to an inverse relationship between language redundancy and duration. The inverse relationship improves communication robustness by spreading information more evenly across the speech signal, yielding a smoother signal redundancy profile. We argue that prosodic prominence is a linguistic means of achieving smooth signal redundancy. Prosodic prominence increases syllable duration and coincides to a large extent with unpredictable sections of speech, and thus leads to a smoother signal redundancy. The results of linear regressions carried out between measures of redundancy, syllable duration and prosodic structure in a large corpus of spontaneous speech confirm: (1) an inverse relationship between language redundancy and duration, and (2) a strong relationship between prosodic prominence and duration. The fact that a large proportion of the variance predicted by language redundancy and prosodic prominence is nonunique suggests that, in English, prosodic prominence structure is the means with which constraints caused by a robust signal requirement are expressed in spontaneous speech.

In this chapter, I discuss experimental evidence for the stretches of speech whose durations are affected by phrasal stress (also called the domain of accentual lengthening). This topic relates to Vincent van Heuven’s work onthe phonetic correlates of stress. I summarize two findings, namely (1) phrasal stress can affect the duration of multiple syllables, and (2) the durational effects of phrasal stress can be influenced by constituent structure. I then discuss two interpretations of these findings (1) that phrasal stress lengthens a continu-ous domain, and (2) that it targets multiple sites, some of which appear to be optional. I present evidence that supports the second interpretation, and end by discussing remaining problems and questions.

Segments and syllables with identical distinctive feature specifications in the lexicon can be produced with strikingly different durations in different contexts, depending for example on the location of a lexical word boundary. In a study of 11 triads like tune acquire, tuna choir and tune a choir, durational differences between, e.g.,tune acquire and tuna choir occurred on either side of the word boundary in a variety of prominence contexts, broadly confirming earlier findings in the literature for a more limited set of stimuli. In general, duration measurements fortune ♯a♯choir tokens were found to be intermediate between those oftune ♯acquire and tuna♯choir, suggesting that boundaries at function words are weaker than boundaries between two content words. In addition, an investigation of the distribution of durational differences across and within syllables was conducted to evaluate five duration adjustment mechanisms proposed in the literature. Support was found for word-initial lengthening, polysyllabic shortening, accentual lengthening, and syllable ratio equalization, but not for word-final lengthening.

Close examination of studies concerned with the distribution of accentual lengthening in Dutch and English reveals that the differences previously found between these two languages may be the result of different experimental designs. Results of new experiments on Dutch using the same conditions as were used in the English experiments indicate that these two languages are indeed more similar than they were previously thought to be; in both languages, all syllables within an accented word are lengthened to some degree, as compared to a baseline unaccented condition, however a greater amount of lengthening is found on an adjacent syllable to the right of the pitch accented syllable than on an adjacent syllable to the left. Furthermore, the data suggest that only the boundaries of syllables and of (syntactic) words influence the distribution of accentual lengthening.

Results of four experiments suggest modifications of Turk and Sawusch's 1997 hypothesis that accentual lengthening occurs throughout a within-word foot-sized domain, and is blocked by its boundaries. Instead, results suggest that (1) a relatively large amount of accentual lengthening occurs on the syllable (primarily its onset and nucleus) with which the pitch accent is associated, (2) there are relatively large rightward effects on syllables adjacent to the pitch accented syllable within a word, and (3) small leftward effects within a word for some speakers. These effects are attenuated, but not necessarily blocked, by the boundaries of a unit the size of an orthographic word, perhaps a prosodic word or clitic group. Both the left edge of a pitch accented syllable and the left and right edges of a word-sized unit thus appear to attenuate the spread of accentual lengthening, which can extend throughout all syllables in a trisyllabic word with primary stress on the initial syllable.

Scottish Gaelic is an endangered language with very few fluent speakers under 60. Recordings were collected in the neighbourhood of Greater Bernera, Lewis, from 11 native speakers. Aerodynamic and palatographic data were collected from one 70-year-old male speaker. Palatographic data made in 1955 by Frederick Macaulay, a Gaelic speaker from South Uist, provided additional information. Analysis showed that all the stops were voiceless unaspirated or aspirated, with the aspirated stops being preaspirated intervocalically. Spectra of various consonants were also determined. Vowel analyses showed the nature of the 7 long and short vowels. Special attention was paid to the back unrounded vowels. Problems of syllabicity were examined and shown to affect pitch contours.

The experiments presented in this paper were designed to determine which linguistic unit, if any, serves as the domain of the durational effects of accent. Results from both experiments suggest that the durational effects of accent are bounded by a linguistic unit. Results from Experiment 1 suggest that the durational effects of accent extend beyond the syllable nucleus or rime. Results from Experiment 2 show that in disyllabic words, word-final, but not word-initial, unstressed syllables are lengthened under accent. These results suggest that the domain of accentual lengthening begins with an accented syllable and can include at least one following unstressed syllable within a word.

In this tutorial we present evidence that, because syntax does not fully predict the way that spoken utterances are organized, prosody is a significant issue for studies of auditory sentence processing. We describe the basic elements and principles of current prosodic theory, review the psycholinguistic evidence that supports an active role for prosodic structure in sentence representation, and provide a road map of references that contain more complete arguments about prosodic structure and prominence. Because current theories do not predict the precise prosodic shape that a particular utterance will take, it is important to determine the prosodic choices that a speaker has made for utterances that are used in an auditory sentence processing study. To this end, we provide information about practical tools such as systems for signal display and prosodic transcription, and several caveats which we have found useful to keep in mind.

The Head-Turn Preference Procedure (HPP) is valuable for testing perception of sustained auditory materials, particularly speech. This article presents a detailed description of the current version of HPP, new evidence of the objectivity of measurements within it, and an account of recent modifications.