Pre-boundary Lengthening Research Articles

Preboundary lengthening and articulatory strengthening in Korean as an edge-prominence language

This study examined preboundary lengthening and other kinematic characteristics of articulatory gestures in CV.CV and CV.CVC before prosodic boundaries in Korean. Preboundary lengthening was found to be extended to initial syllables in both CV.CVand CV.CVC, while its magnitude was largest on the final syllable. The preboundary lengthening effect was also reflected in the time-to-peak velocity (acceleration duration), but only on gestures of the final syllable. Preboundary lengthening was accompanied by substantial increase in both displacement and peak velocity, showing domain-final articulatory strengthening. This articulatory strengthening effect on preboundary gestures (at the right edge of prosodic constituent) was largely dovetailed with the notion of an edge-prominence language where boundary marking is assumed to be closely related with prominence lending. These results were compared in two different conditions driven by information structure (‘new’ vs. ‘given’) and were discussed to understand the observed kinematic pattern in dynamical terms in the theoretical framework of the π-gesture model. 

Increased Pre-Boundary Lengthening Does Not Enhance Implicit Intonational Phrase Perception in European Portuguese: An EEG Study.

Prosodic phrasing is the segmentation of utterances into prosodic words, phonological phrases (smaller units) and intonational phrases (larger units) based on acoustic cues-pauses, pitch changes and pre-boundary lengthening. The perception of prosodic boundaries is characterized by a positive event-related potential (ERP) component, temporally aligned with phrase boundaries-the Closure Positive Shift (CPS). The role of pre-boundary lengthening in boundary perception is still a matter of debate: while studies on phonological phrase boundaries indicate that all three cues contribute equally, approaches to intonational phrase boundaries highlight the pause as the most powerful cue. Moreover, all studies used explicit boundary recognition tasks, and it is unknown how pre-boundary lengthening works in implicit prosodic processing tasks, characteristic of real-life contexts. In this study, we examined the effects of pre-boundary lengthening (original, short, and long) on the EEG responses to intonational phrase boundaries (CPS effect) in European Portuguese, using an implicit task. Both original and short versions showed equivalent CPS effects, while the long set did not elicit the effect. This suggests that pre-boundary lengthening does not contribute to improved perception of boundaries in intonational phrases (longer units), possibly due to memory and attention-related constraints.

The interaction between predictability and pre-boundary lengthening on syllable duration in Taiwan Southern Min.

This study investigated how predictability and prosodic phrasing interact in accounting for the variability of syllable duration in Taiwan Southern Min. Speech data were extracted from 8 hours of spontaneous speech. Three predictability measurements were examined: bigram surprisal, bigram informativity, and lexical frequency. Results showed that higher informativity and surprisal led to longer syllables. As for the interaction with prosodic positions, there was a general weakening of predictability effects for syllables closer to the boundary, especially in the pre-boundary position, where pre-boundary lengthening was the strongest. However, the effect of word informativity appeared to be least modulated by this effect of boundary marking. These findings are consistent with a hypothesis that prosodic structure modulates the predictability effects on phonetic variability. The robustness of informativity in predicting syllable duration also suggests a possibility of stored phonetic variants associated with a word's usual contextual predictability.

Prominence marking in an edge-prominent language - the case of Drehu

This study investigates prosodic correlates of phrasing in Drehu, an Oceanic language from New Caledonia. The analysis is concerned with the demarcation of prosodic levels in the language, namely the Accentual Phrase and the Intonation Phrase. First impressionistic descriptions of Drehu state there is fixed word initial stress, however recent experimental evidence does not support this claim. Instead, it has been suggested that Drehu could be an edge-marking language which relies on right boundary marking. To determine whether the patterns recorded in the literature are borne out, the phonological and phonetic realisation of post-lexical word level prosody is investigated. An experiment was conducted to examine the extent to which fundamental frequency (F0) and duration contribute to boundary marking in Drehu. The results show that F0 cues mark the right boundary of two prosodic levels, the AP and IP, and that the strength of the boundary is related to its level in the prosodic hierarchy. Preboundary lengthening also cues IP boundaries but not AP boundaries.

Prosodic Disambiguation in First and Second Language Production: English and Korean.

This study investigates the use of prosodic cues for syntactic ambiguity resolution by first language (L1) and second language (L2) speakers. In a production experiment, sentences with relative clause attachment ambiguity were elicited in three language conditions: native English speakers' L1 productions as well as Korean-English bilingual speakers' L1 Korean and L2 English productions. The results show that English uses both boundary marking (pause) and relative word prominence (elevated pitch and intensity) for disambiguation, while Korean mainly relies on boundary marking (pre-boundary lengthening and pause). The bilingual speakers have learned to use the English phonological categories such as pitch accents for disambiguation, but their use of phonetic cues to realize these categories still differed from that of native English speakers. In addition, they did not show a significant use of boundary cues. These results are discussed in relation to the typological differences between the prosody of English and of Korean.

Kinematic boundary cues modulate 12-month-old infants’ segmentation of action sequences: An ERP study

Human infants can segment action sequences into their constituent actions already during the first year of life. However, work to date has almost exclusively examined the role of infants' conceptual knowledge of actions and their outcomes in driving this segmentation. The present study examined electrophysiological correlates of infants' processing of lower-level perceptual cues that signal a boundary between two actions of an action sequence. Specifically, we tested the effect of kinematic boundary cues (pre-boundary lengthening and pause) on 12-month-old infants' (N = 27) processing of a sequence of three arbitrary actions, performed by an animated figure. Using the Event-Related Potential (ERP) approach, evidence of a positivity following the onset of the boundary cues was found, in line with previous work that has found an ERP positivity (Closure Positive Shift, CPS) related to boundary processing in auditory stimuli and action sequences in adults. Moreover, an ERP negativity (Negative Central, Nc) indicated that infants’ encoding of the post-boundary action was modulated by the presence or absence of prior boundary cues. We therefore conclude that 12-month-old infants are sensitive to lower-level perceptual kinematic boundary cues, which can support segmentation of a continuous stream of movement into individual action units.

Automatic detection of prosodic boundaries in spontaneous speech.

Automatic speech recognition (ASR) and natural language processing (NLP) are expected to benefit from an effective, simple, and reliable method to automatically parse conversational speech. The ability to parse conversational speech depends crucially on the ability to identify boundaries between prosodic phrases. This is done naturally by the human ear, yet has proved surprisingly difficult to achieve reliably and simply in an automatic manner. Efforts to date have focused on detecting phrase boundaries using a variety of linguistic and acoustic cues. We propose a method which does not require model training and utilizes two prosodic cues that are based on ASR output. Boundaries are identified using discontinuities in speech rate (pre-boundary lengthening and phrase-initial acceleration) and silent pauses. The resulting phrases preserve syntactic validity, exhibit pitch reset, and compare well with manual tagging of prosodic boundaries. Collectively, our findings support the notion of prosodic phrases that represent coherent patterns across textual and acoustic parameters.

Nouns and verbs in the speech signal: Are there phonetic correlates of grammatical category?

AbstractOver the past decades a considerable number of works have observed differences in the phonetic realization of nouns and verbs. The guiding question in most relevant research is whether such differences are caused by grammatical category per se, or are triggered by more general processes of phonetic implementation that impact nouns and verbs differently. Most studies argue for the latter and focus on one particular process or variable, which is advocated to be responsible for the acoustic differences observed. Among the processes mentioned are pre-boundary lengthening, accentuation, and frequency-induced reduction. Due to the focus on monofactorial explanations, an overview and contextualization of the different processes interacting with the noun-verb distinction is yet missing. The present paper aims to fill this gap. This goal is pursed by providing an in-depth discussion of how grammatical category interacts with a number of different processes that affect acoustic realization. To that end results from the literature on the topic are synthesized with new acoustic analyses of noun-verb homophones from spontaneous speech. The analysis shows that differences in acoustic realization between nouns and verbs are caused by the complex interplay of a number of different processes, defying simple, monofactorial explanations.

Recursion of Phonological Phrase: Views from the Jordanian Arabic dialect of Irbid

In the original model of Prosodic Hierarchy (Selkirk 1984, 1986; Nespor &Vogel 1986), the prosodic representation was partly autonomous from the syntactic structure, and prosodic recursion was not possible. Recently, it has been proposed in Match Theory (Selkirk 2011) that each prosodic unit has a corresponding syntactic constituent, and prosodic recursion exists, as proposed in some recent empirical studies (Féry and Truckenbrodt 2005; Wagner 2005, 2010, Selkirk 2009, 2011, Itô & Mester 2012, 2013; Elfner 2012among others). This paper empirically investigates the phonological phrase construction in Jordanian Arabic as spoken in Irbid. The empirical results indicate that phonological phrases match XPs and are marked by low phrase accents and pre-boundary lengthening. They also suggest that syntactic nesting motivates prosodic recursion: a nested XP matches a recursive phonological phrase which is cued by gradient pre-boundary lengthening. However, a recursive phonological phrase is limited to two subcategories, i.e. a minimal and maximal layer. In accord with that, prosodic recursion is neither prohibited as proposed in the early version of Strict Layer Hypothesis (Selkirk 1984, 1986; Nespor &Vogel 1986), nor freely allowed to perfectly mirror syntactic nesting as in Match Theory (Selkirk 2011).

Phonetic effects of grammatical category: How category-specific prosodic phrasing and lexical frequency impact the duration of nouns and verbs

This paper is concerned with phonetic correlates of grammatical category, specifically the finding that nouns are pronounced with greater duration than verbs in discourse. Most previous research has attributed this difference to the sentence positions that the two grammatical categories occupy and concomitant prosodic effects. Based on previous findings, we test two further effects, namely a category-specific effect on prosodic phrasing, which leads to stronger prosodic boundaries after nouns than verbs even in maximally similar syntactic contexts, and a reductive effect of lexical frequency leading to shorter durations of the more frequent word. These effects are tested in a production study investigating durational differences of twelve noun–verb homophone pairs in English in two clause-medial contexts. We find evidence for both effects: prosodic boundaries are stronger after nouns than verbs across all conditions, resulting in greater durations of nouns due to pre-boundary lengthening. Furthermore, differences in frequency result in a reduced duration of the homophone of the pair which has the greater frequency. We propose an explanation in which phonetic effects of grammatical category are caused by the interplay of sentence prosody, category-specific prosodic phrasing and lexical frequency.

The interaction between lexical prominence and pre-boundary lengthening in Japanese

Pre-boundary lengthening, also known as phrase-final lengthening, is a well-established phenomenon. In stress languages, pre-boundary lengthening has been shown to interact with lexical prominence (i.e., stress), affecting the boundary-adjacent constriction gestures in stress-final words, but being attracted towards the stressed syllable when stress is non-final. However, the interaction between pre-boundary lengthening and lexical prominence in a language with lexical pitch accent, like Japanese, is not well understood. The current study uses kinematic data collected with Electromagnetic Articulography (EMA) to investigate this interaction in Japanese. We examine pre-boundary lengthening in trisyllabic phrase-final words as a factor of pitch accent position (initial-accented, medial-accented, final-accented, and no accent). Preliminary results based on duration measurements of the consonant constriction gestures comprising the phrase-final words show that in words with no pitch accent, pre-boundary lengthening has a progressive effect extending two syllables away from the right edge of the phrase, being strongest in the word-final syllable. If pitch accent is present, pre-boundary lengthening is affected by the former’s position. The lengthening effect is limited to the final syllable in initial- and medial-accented words, and disappears in final-accented words. Typological dimensions of the interaction between prominence and boundaries are discussed. [Work supported by NSF.]

Preboundary lengthening in Japanese: To what extent do lexical pitch accent and moraic structure matter?

In this acoustic study, preboundary lengthening (PBL) in Japanese is investigated in relation to the prosodic structure in disyllabic words with different moraic and pitch accent distributions. Results showed gradient progressive PBL effects largely independent of the mora count. The domain of PBL is better explained by the syllable structure than the moraic structure. PBL, however, is attracted toward a non-final moraic nasal, showing some role of the mora. The initial pitch accent does not attract PBL directly, but it suppresses PBL of the final rime as a way of maintaining the relative prominence, showing a language-specific PBL modulation.

Parallels in Processing Boundary Cues in Speech and Action.

Speech and action sequences are continuous streams of information that can be segmented into sub-units. In both domains, this segmentation can be facilitated by perceptual cues contained within the information stream. In speech, prosodic cues (e.g., a pause, pre-boundary lengthening, and pitch rise) mark boundaries between words and phrases, while boundaries between actions of an action sequence can be marked by kinematic cues (e.g., a pause, pre-boundary deceleration). The processing of prosodic boundary cues evokes an Event-related Potentials (ERP) component known as the Closure Positive Shift (CPS), and it is possible that the CPS reflects domain-general cognitive processes involved in segmentation, given that the CPS is also evoked by boundaries between subunits of non-speech auditory stimuli. This study further probed the domain-generality of the CPS and its underlying processes by investigating electrophysiological correlates of the processing of boundary cues in sequences of spoken verbs (auditory stimuli; Experiment 1; N = 23 adults) and actions (visual stimuli; Experiment 2; N = 23 adults). The EEG data from both experiments revealed a CPS-like broadly distributed positivity during the 250 ms prior to the onset of the post-boundary word or action, indicating similar electrophysiological correlates of boundary processing across domains, suggesting that the cognitive processes underlying speech and action segmentation might also be shared.

The glottal stop between segmental and suprasegmental processing: The case of Maltese

• Maltese uses the glottal stop as both an underlying and epenthetic segment. • Words with and without an initial underlying glottal stop can become homophonous. • Epenthetic glottal stops are partly prosodically conditioned. • Listeners take prosodic information into account in the late stages of speech perception. • The interaction between prosodic and segmental processing needs to be considered. Many languages mark vowel-initial words with a glottal stop. We show that this occurs in Maltese, even though the glottal stop also occurs as a phoneme in Maltese. As a consequence, words with and without an underlying (phonemic) glottal stop (e.g., a glottal stop-zero minimal pair qal /Ɂɑ:l/ vs. ghal /ɑ:l/ Engl., ‘he said’-‘because’) can become homophonous in connected speech. We first tested the extent of this phonetic marking of vowel-initial words in a production experiment and found that even in fluent productions, about half of the vowel-initial words are marked with an epenthetic glottal stop. The epenthetic glottal stop is more likely to occur when the preceding word is longer, showing a kind of preboundary lengthening at a phrase-level prosodic boundary. A subsequent perception study (Experiment 2) using a two-alternative forced-choice task with a minimal pair of a glottal stop-initial and a vowel-initial word indicated that listeners are sensitive to the durationally conditioned prosodic context before the test word, and they are more likely to perceive a vowel-initial word when the preceding word is lengthened. An additional eye-tracking study (Experiment 3) using onset-overlap pairs (e.g., qafla /Ɂɑflɑ/ - afda, /ɑfdɑ/ → [Ɂɑfda], Engl., ‘to trust’ - ‘chord’) showed no early influence of prosodic cues on segmental processing. But a gating experiment (Experiment 4) replicated the prosodic effect observed in Experiment 2. Taken together, our results indicate an interaction between prosodic processing and segmental processing that comes into effect relatively late in speech processing.

Automatic Extraction of Quranic Lexis Representing Two Different Notions of Linguistic Salience: Keyness and Prosodic Prominence

Abstract This paper presents two sets of lexical items automatically extracted from the Arabic Qur’ān, and denoting two different notions of linguistic salience: keyness and prosodic prominence. Our novel hypothesis investigates a possible correlation between them. Our novel findings discover distributionally significant keywords that also occur strategically in phrase-final position so as to maximise their prominence, and thus meaningfulness, for reader, reciter, and aural recipient. Our methodology first computes Quranic keywords via the Corpus Linguistics technique of Keyword Extraction, and maps them to major Quranic themes in Islamic scholarship. Next, we implement a bespoke algorithm for rule-based capture of words annotated with madd or prolongation, a specific type of prosodic highlighting in Quranic recitation rules or tajwīd. We find it especially interesting that the concept of final syllable lengthening (madd before pause) is encoded in tajwīid and effectively demarcates phrase boundaries in the Qur’ān. We concentrate on nominal keywords (i.e. nouns and adjectives) since these are more likely to be aligned with phrase edges and to bear the hallmarks of pre-boundary lengthening. This correlation between keyness and prominence occurs 43.29% of the time in our data, since 526 keywords appear in our extracted subset of nominal types tagged with madd before pause: ((526/1215)*100). Finally, we identify which Quranic keywords are most likely to be annotated with enhanced prolongation in the final syllable before pause, using an easy-to-interpret, single value metric: the Laplace Point Estimate. Keywords that emerge as semantically weighted in terms of both distributional and prosodic significance are most likely to reflect the Quranic themes of God, Nature, and Eschatology.

Alongamento em fronteira de frase entoacional no Português do Brasil

Este artigo investiga o fenômeno do alongamento pré-fronteira em dados do Português Brasileiro. Para tanto, apresenta um experimento de produção delineado para verificar a ocorrência do fenômeno a partir de sentenças em contraste, caracterizadas pela mesma cadeia segmental, mas por fraseamentos prosódicos diferentes. A fronteira de frase entoacional foi eleita para o presente estudo, uma vez que se trata de uma fronteira mais robusta no interior da hierarquia prosódica e, por consequência, porque apresenta a tendência de carregar mais pistas fonéticas para sua demarcação. Não obstante, a referida fronteira foi também selecionada pela sua relevância no fraseamento prosódico e por seu consequente papel de importância no processamento da fala. Como principal resultado, o estudo apresenta amparo estatístico que permite afirmar a ocorrência do alongamento pré-fronteira nos dados analisados, resultado que é contrastado com achados anteriores para o Português. Com os resultados apresentados, o presente artigo propõe uma breve discussão sobre o papel desempenhado pelo método na análise de dados linguísticos, especialmente na área de fonética e fonologia.

Prosody-driven syntax learning is robust to impoverished pitch and spectral cues.

Across languages, prosodic boundaries tend to align with syntactic boundaries, and both infant and adult language learners capitalize on these correlations to jump-start syntax acquisition. However, it is unclear which prosodic cues-pauses, final-syllable lengthening, and/or pitch resets across boundaries-are necessary for prosodic bootstrapping to occur. It is also unknown how syntax acquisition is impacted when listeners do not have access to the full range of prosodic or spectral information. These questions were addressed using 14-channel noise-vocoded (spectrally degraded) speech. While pre-boundary lengthening and pauses are well-transmitted through noise-vocoded speech, pitch is not; overall intelligibility is also decreased. In two artificial grammar experiments, adult native English speakers showed a similar ability to use English-like prosody to bootstrap unfamiliar syntactic structures from degraded speech and natural, unmanipulated speech. Contrary to previous findings that listeners may require pitch resets and final lengthening to co-occur if no pause cue is present, participants in the degraded speech conditions were able to detect prosodic boundaries from lengthening alone. Results suggest that pitch is not necessary for adult English speakers to perceive prosodic boundaries associated with syntactic structures, and that prosodic bootstrapping is robust to degraded spectral information.

Articulatory characteristics of preboundary lengthening in interaction with prominence on tri-syllabic words in American English.

This study investigated articulation of preboundary lengthening (PBL) in tri-syllabic pseudo words (bábaba, babába, bababá) in American English. Results from 10 speakers showed that PBL was modulated by the degree of prominence, i.e., the less prominent, the more PBL. PBL was attracted to the penultimate stressed syllable but only when the word received no pitch accent whereas the antepenultimate syllable showed no PBL. Kinematically, PBL was accompanied by a larger movement along with an increase in peak velocity, showing a kind of boundary-related articulatory strengthening, although there was some evidence of temporal expansion possibly due to lowered stiffness.

Prosodic bootstrapping of syntax from cochlear implant-simulated speech

It has been well-documented that prosodic boundaries often align with syntactic boundaries, and that both infants and adults capitalize on prosodic cues to bootstrap knowledge of syntax. However, it is less clear which prosodic cues—pre-boundary lengthening, pauses, and/or pitch resets across boundaries—are necessary for this bootstrapping to occur. It is also unknown how syntax acquisition is impacted for listeners who do not have access to the full spectrum of prosodic information. These questions were addressed using noise vocoded speech, which simulates speech perceived through a cochlear implant. While pre-boundary lengthening and pauses are well-transmitted through noise vocoded speech, pitch is not. In two experiments, adults listening to noise vocoded speech performed similarly to adults listening to unmanipulated speech in syntax acquisition tasks. This suggests that lengthening and pause cues alone are sufficient to facilitate acquisition of some syntactic structures, and that listeners with cochlear implants may be able to bootstrap syntax using prosody in a similar way as individuals with normal hearing.

Acoustic features of prosodic boundary by Chinese learners of English as a second language

The production and perception of prosodic boundary have been well studied in English, but the research regarding to English as a second language (L2) is sparse. It has been shown that Chinese and English employ different acoustic features to mark prosodic boundary in production. Thus, this study aims to find out whether the Chinese learners of English employ the same strategy to convey prosodic boundary in English as the native speakers do. Ten pairs of syntactically ambiguous utterances composed of two or three food items were designed, with 10 pairs of filler utterances half randomized together. Ten speakers (5 males and 5 females) from Shanghai who passed the annual national examination CET (College English Test) Band 6 were asked to read the utterances. The results showed that, similar to the native speakers, Chinese learners also use pre-boundary lengthening, pause duration and pitch reset to signal the prosodic boundary in English. However, their pitch contour of the pre-boundary syllable is falling under boundary condition, and is rising under non-boundary condition, which is opposite to that of the native English speakers. This result will have an implication in L2 English teaching and learning.