Sahyang Kim

Communicatively driven versus prosodically driven hyper-articulation in Korean

Abstract This study investigated how three different kinds of hyper-articulation, one communicatively driven (in clear speech), and two prosodically driven (with boundary and prominence/focus), are acoustic-phonetically realized in Korean. Several important points emerged from the results obtained from an acoustic study with eight speakers of Seoul Korean. First, clear speech gave rise to global modification of the temporal and prosodic structures over the course of the utterance, showing slowing down of the utterance and more prosodic phrases. Second, although the three kinds of hyper-articulation were similar in some aspects, they also differed in many aspects, suggesting that different sources of hyper-articulation are encoded separately in speech production. Third, the three kinds of hyper-articulation interacted with each other; the communicatively driven hyper-articulation was prosodically modulated, such that in a clear speech mode not every segment was hyper-articulated to the same degree, but prosodically important landmarks (e.g., in IP-initial and/or focused conditions) were weighted more. Finally, Korean, a language without lexical stress and pitch accent, showed different hyper-articulation patterns compared to other, Indo-European languages such as English—i.e., it showed more robust domain-initial strengthening effects (extended beyond the first initial segment), focus effects (extended to V1 and V2 of the entire bisyllabic test word) and no use of global F0 features in clear speech. Overall, the present study suggests that the communicatively driven and the prosodically driven hyper-articulations are intricately intertwined in ways that reflect not only interactions of principles of gestural economy and contrast enhancement, but also language-specific prosodic systems, which further modulate how the three kinds of hyper-articulations are phonetically expressed.

The use of phrase-level prosodic information in lexical segmentation: evidence from word-spotting experiments in Korean.

This study investigated the role of phrase-level prosodic boundary information in word segmentation in Korean with two word-spotting experiments. In experiment 1, it was found that intonational cues alone helped listeners with lexical segmentation. Listeners paid more attention to local intonational cues (...H#L...) across the prosodic boundary than the intonational information within a prosodic phrase. The results imply that intonation patterns with high frequency are used, though not exclusively, in lexical segmentation. In experiment 2, final lengthening was added to see how multiple prosodic cues influence lexical segmentation. The results showed that listeners did not necessarily benefit from the presence of both intonational and final lengthening cues: Their performance was improved only when intonational information contained infrequent tonal patterns for boundary marking, showing only partially cumulative effects of prosodic cues. When the intonational information was optimal (frequent) for boundary marking, however, poorer performance was observed with final lengthening. This is arguably because the phrase-initial segmental allophonic cues for the accentual phrase were not matched with the prosodic cues for the intonational phrase. It is proposed that the asymmetrical use of multiple cues was due to interaction between prosodic and segmental information that are computed in parallel in lexical segmentation.

Prosodic strengthening on the /s/-stop cluster and the phonetic implementation of an allophonic rule in English

Abstract This acoustic study investigates effects of boundary and prominence on the temporal structure of s#CV and #sCV in English, and on the phonetic implementation of the allophonic rule whereby a voiceless stop after /s/ becomes unaspirated. Results obtained with acoustic temporal measures for /sCV/ sequences showed that the segments at the source of prosodic strengthening ( i.e. , /s/ in #sCV for boundary marking and the nucleus vowel for prominence marking) were expanded in both absolute and relational terms, whereas other durational components distant from the source ( e.g. , stop closure duration in #sCV ) showed temporal expansion only in the absolute measure. This suggests that speakers make an extra effort to expand the very first segment and the nucleus vowel more than the rest of the sequence in order to signal the pivotal loci of the boundary vs. the prominence information. The potentially ambiguous s#CV and #sCV sequences ( e.g. , ice#can vs. eye#sca n) were never found to be neutralized even in the phrase-internal condition, cuing the underlying syllable structures with fine phonetic detail. Most crucially, an already short lag VOT in #sCV (due to the allophonic rule) was shortened further under prosodic strengthening, which was interpreted as enhancement of the phonetic feature {voiceless unaspirated}. It was proposed that prosodic strengthening makes crucial reference to the phonetic feature system of the language and operates on a phonetic feature, including the one derived by a language-specific allophonic rule. An alternative account was also discussed in gestural terms in the framework of Articulatory Phonology.

Supralaryngeal articulatory signatures of three-way contrastive labial stops in Korean

Abstract This study investigates how the three-way contrastive bilabial stops (/p⁎,ph,p/, called fortis, aspirated and lenis, respectively) in word-medial position in Korean are distinct kinematically at the supralaryngeal articulatory level. Results of a magnetometer experiment with seven speakers of Seoul Korean showed that the three-way contrastive stops in VCV sequences (V=/i/ or /a/) are indeed manifested at the supralaryngeal level—not only in consonantal articulation, but also in vocalic articulation of their adjacent vowels. Several specific points have emerged. First, stops were three-way distinct in constriction degree and constriction duration (/p*/>/ph/>/p/). Second, their contrast was also evident in temporal dimensions of the vocalic tongue movement with a three-way distinct pattern (/p*/>/ph/>/p/), and of the lip opening movement with a two-way distinction (/p*,ph/>/p/). Third, consonantal strength was further reflected in V-to-V coarticulation, such that longer constriction triggered more reduction of V-to-V coarticulation. However, there was a case (for /i/ in carryover direction) in which coarticulatory reduction was still observed even when the duration was factored in, showing duration-independent V-to-V coarticulatory resistance associated with the fortis and aspirated stops. Fourth, stable coordination was observed between the lip constriction and the vocalic tongue movement which is in line with previous findings in Japanese and English, suggesting cross-linguistic similarities in consonant–vowel gestural coordination regardless of the rhythmic structure of a given language.

How does prosody influence speech categorization

We thank our graduate student assistants, Daejin Kim, Miroo Lee and Yuna Baek for assisting us with data acquisition. This work was supported by the research fund of Hanyang University (HY-2013) to the corresponding author (T. Cho).

Preboundary lengthening and preaccentual shortening across syllables in a trisyllabic word in English

This study demonstrates some new aspects of preboundary lengthening and preaccentual shortening on a test word banana in American English. Preboundary lengthening was found to be extended to the initial unstressed syllable beyond the main-stressed syllable, presenting more complexity than has previously been assumed. Preaccentual shortening was observed regardless of boundary strength or the stress pattern (trochaic vs iambic) of the following context word, suggesting that it operates globally at an utterance level. The locus of preaccentual shortening, however, was modulated by prosodic boundary: It is realized on the final vowel IP-finally but on the non-final stressed vowel IP-medially.

Prosodically-conditioned fine-tuning of coarticulatory vowel nasalization in English

Abstract This study explores the relationship between prosodic strengthening and linguistic contrasts in English by examining temporal realization of nasals ( N -duration) in CV N # and # N VC, and their coarticulatory influence on vowels (V-nasalization). Results show that different sources of prosodic strengthening bring about different types of linguistic contrasts. Prominence enhances the consonant׳s [nasality] as reflected in an elongation of N -duration, but it enhances the vowel׳s [orality] (rather than [nasality]) showing coarticulatory resistance to the nasal influence even when the nasal is phonologically focused (e.g., m ob - b ob; bo mb - bo b ). Boundary strength induces different types of enhancement patterns as a function of prosodic position (initial vs. final). In the domain-initial position, boundary strength reduces the consonant׳s [nasality] as evident in a shortening of N-duration and a reduction of V-nasalization, thus enhancing CV contrast. The opposite is true with the domain-final nasal in which N -duration is lengthened accompanied by greater V-nasalization, showing coarticulatory vulnerability. The systematic coarticulatory variation as a function of prosodic factors indicates that V-nasalization as a coarticulatory process is indeed under speaker control, fine-tuned in a linguistically significant way. In dynamical terms, these results may be seen as coming from differential intergestural coupling relationships that may underlie the difference in V-nasalization in CVN# vs . #NVC. It is proposed that the timing initially determined by such coupling relationships must be fine-tuned by prosodic strengthening in a way that reflects the relationship between dynamical underpinnings of speech timing and linguistic contrasts.

Effects of prosodic boundary and syllable structure on the temporal realization of CV gestures

Abstract An articulatory study was conducted to explore effects of prosodic boundary and syllable structure on temporal realizations of /ma/ in C♯V vs. ♯CV in Korean (where ‘♯’ denotes an Intonational Phrase or a Word boundary). The vocalic gesture underwent boundary-induced lengthening more in C♯ V than in ♯C V , implying that the boundary effect is largely localized to the initial element whether consonantal or vocalic. CV coordination patterns were temporally neutralized between ♯CV and C♯V in the phrase-internal Word boundary condition, showing a possible ‘resyllabifiation’ of ‘C’ with the following vowel in C♯V in the articulatory temporal measures taken in the present study. It was suggested that CV gestures in C♯V, whose phasing relationship has to be determined postlexically, reorganize temporally in an in-phase coupling mode just like the way CV gestures are phased in ♯CV. Finally, while there was leftward shifting of the consonantal gesture in C♯V with some temporal variability across an IP vs. a Word boundary, intergestural timing in ♯CV remained invariant regardless of boundary strength. But the most stable temporal pattern was observed with an IP boundary in ♯CV, interpretable as an important temporal characteristic of domain-initial strengthening. Some of these results were further discussed in terms of their implications for the theory of π-gesture and the gestural coupling model of syllable structure.

What are the letters of speech? Testing the role of phonological specification and phonetic similarity in perceptual learning

Abstract Recent studies on perceptual learning have indicated that listeners use some form of pre-lexical abstraction (an intermediate unit) between the acoustic input and lexical representations of words. Patterns of generalization of learning that can be observed with the perceptual learning paradigm have also been effectively examined for exploring the nature of these intermediate pre-lexical units. We here test whether perceptual learning generalizes to other sounds that share an underlying or a phonetic representation with the sounds based on which learning has taken place. This was achieved by exposing listeners to phonologically altered (tensified) plain (lax) stops in Korean (i.e., underlyingly plain stops are produced as tense due to a phonological process in Korean) with which listeners learned to recalibrate place of articulation in tensified plain stops. After the recalibration with tensified plain stops, Korean listeners generalized perceptual learning (1) to phonetically similar but underlyingly (phonemically) different stops (i.e., from tensified plain stops to underlyingly tense stops) and (2) to phonetically dissimilar but underlyingly (phonemically) same stops (i.e., from tensified plain stops to non-tensified ones) while generalization failed to phonetically dissimilar and underlyingly different consonants (aspirated stops and nasals) even though they share the same [place] feature. The results imply that pre-lexical units can be better understood in terms of phonetically-definable segments of granular size rather than phonological features, although perceptual learning appears to make some reference to the underlying (phonemic) representation of speech sounds based on which learning takes place.

Articulatory reflexes of the three-way contrast in labial stops and kinematic evidence for domain-initial strengthening in Korean

We are grateful to the Korean speakers who participated in our EMA experiment. We also thank three anonymous reviewers and the Editor (Adrian Simpson) for very constructive comments. This work was supported by the research fund of Hanyang University (HY-2015) to the first author (T. Cho).