Publications

A recent study (Kim & Cho, 2013, The Journal of the Acoustical Society of America) reported that the perception of a prosodic boundary leads to a shift in a stop-identification function in English, so that stops with a relatively long VOT are accepted as voiced if occurring after a major prosodic boundary. Even Korean learners of English showed such a shift. This shift would seem to result from compensation for post-boundary lengthening effects (or domain-initial strengthening) and thereby help to overcome the invariance problem in speech perception. In two experiments, we ask how this effect comes about. The first experiment tested whether a simple adjustment to a change in overall speaking rate would be sufficient to account for the shift. Results showed that while the global speaking-rate change modulates phonetic categorization in a similar way as a change in the prosodic boundary strength, the speaking-rate effect is not sufficient to explain the boundary effect. That is, there was a more robust shift in a stop identification function with localized slowing down of the final syllable due to an intonational phrase (IP) boundary than with global slowing down of speaking rate. The second experiment therefore investigated the contribution of an F0 cue to the observed perceptual shift and found that the presence or absence of the F0 cue did not mediate the effect of prosodic boundaries on phonetic categorization. This suggests that a perception shift in phonetic categorization stems primarily from the listeners' adjustment to temporal variation, though its source is different from the speaking rate. The results are considered in terms of two possible accounts: one that takes both the boundary-induced and the speaking rate-induced effects as listeners' adjustments to low-level temporal variation, and the other that separates them by taking the boundary-induced effects to arise with computation of higher-level prosodic structure, given that the source of the localized slowing down effect is a prosodic boundary.

We thank the Korean speakers for their participation, and the reviewers for their helpful comments. This work was supported in part by the Ministry of Education of the Republic of Korea and the National Research Foundation of Korea (NRF2018S1A5A2A03036736).

Recent studies on perceptual learning have indicated that listeners use intermediate units between the acoustic input and lexical representations of words. The same paradigm may also reveal the nature of these intermediate units based on patterns of generalization of learning. We here test whether learning generalizes to other units of the same underlying or surface representation. This was achieved by exposing listeners to tensified Korean stops (i.e., underlying plain stops produced as tense due to a phonological process) and testing the consequences for later presented underlying tense or plain stops. Our results show that learning generalizes to underlying tense stops, while generalization to underlying plain stops could not be found. This indicates that the difference in the underlying phonological representation as tense or plain do not hinder learning as long as there is phonetic similarity on the surface.

This article provides some supplementary analysis data of speech production and perception of glottal stops in the Semitic language Maltese. In Maltese, a glottal stop can occur as a phoneme, but also as a phonetic marker of vowel-initial words (as in the case with Germanic languages like English). Data from four experiments are provided, which will allow other researchers to reproduce the results and apply their own data-analysis techniques to these data for further data exploration. A production experiment (Experiment 1) investigates how often the glottal marking of vowel-initial words occurs (causing vowel-initial words to be ambiguous with words starting with a glottal stop as a phoneme) and whether the glottal gesture for this marking can be differentiated from an underlying (phonemic) glottal stop in its acoustic properties. Experiments 2 to 4 investigate how and to what extent Maltese listeners perceive glottal markings as lexical (phonemic) or epenthetic (phonetic), using a two-alternative forced choice task (Experiment 2), a visual-world eye tracking task with printed target words (Experiment 3) and a gating task (Experiment 4). A full account of theoretical consequences of these data can be found in the full length article entitled "The glottal stop between segmental and suprasegmental processing: The case of Maltese" [1].

This study investigated how the L1 phonetics-prosody interface transfers to L2 by examining prosodic strengthening effects (due to prosodic position and focus) on English voicing contrast (bad-pad) as produced by Korean vs English speakers. Under prosodic strengthening, Korean speakers showed a greater F0 difference due to voicing than English speakers, suggesting that their experience with the macroprosodic use of F0 in Korean transfers into L2. Furthermore, Korean speakers produced voiced stops with low F0 and short voice onset time as English speakers did, although such a cue pairing is absent in Korean, showing dissociation of cues from L1 segments for L2 production.

No abstract is provided for this article.

In this special collection entitled Marking 50 Years of Research on Voice Onset Time and the Voicing Contrast in the World's Languages, we have compiled eleven studies investigating the voicing contrast in 19 languages. The collection provides extensive data obtained from 270 speakers across those languages, examining VOT and other acoustic, aerodynamic and articulatory measures. The languages studied may be divided into four groups: 'aspirating' languages with a two-way contrast (English, three varieties of German); 'true voicing' languages with a two-way contrast (Russian, Turkish, Brazilian Portuguese, two Iranian languages Pashto and Wakhi); languages with a three-way contrast (Thai, Vietnamese, Khmer, Yerevan Armenia, three Indo-Aryan languages, Dawoodi, Punjabi and Shina, and Burushaki spoken in India); and Indo-Aryan languages with a more than three-way contrast (Jangli and Urdu with a four-way contrast, and Sindhi and Siraiki with a five-way contrast). We discuss the cross-linguistic data, focusing on how much VOT alone tell s us above the voicing contrast in these languages, and what other phonetic dimensions (such as consonant-induced F0 and voice quality) are needed for a complete understanding of laryngeal contrast in these languages. Implications for various issues emerge: universal phonetic feature systems, effects of language contact on linguistic levelling, and the relation between laryngeal contrast and supralaryngeal articulation. The cross-linguistic VOT data also lead us to discuss how the distribution of VOT as measured acoustically may allow us to infer the underlying articulation and how it might be approached in gestural phonologies. The discussion on these multiple issues sparks new questions to be resolved, and provide indications of where the field may be best directed in exploring laryngeal contrast in voicing in the world's languages.

This study investigates focus and boundary effects on Korean nasal consonants and vowel nasalization. Under focus, nasal consonants lengthen in CVN# but shorten in #NVC, enhancing [nasal] vs [oral]. Vowels resist nasalization under focus, enhancing [oral]. Domain-initial nasal consonants denasalize, exercising no coarticulatory influence. Domain-final nasal consonants shorten counter to expectation, although vowel nasalization increases. Comparison with English data reveals similarities (focus-induced coarticulatory resistance) despite cross-linguistic differences in marking prominence, but it also suggests that prosodic-structural conditioning of non-contrastive vowel nasalization, albeit based on phonetic underpinnings of coarticulatory process, is fine-tuned in language-specific ways, resulting in cross-linguistic variation.

How do Dutch and Korean listeners use acoustic–phonetic information when learning words in an artificial language? Dutch has a voiceless ‘unaspirated’ stop, produced with shortened Voice Onset Time (VOT) in prosodic strengthening environments (e.g., in domain-initial position and under prominence), enhancing the feature {−spread glottis}; Korean has a voiceless ‘aspirated’ stop produced with lengthened VOT in similar environments, enhancing the feature {+spread glottis}. Given this cross-linguistic difference, two competing hypotheses were tested. The phonological-superiority hypothesis predicts that Dutch and Korean listeners should utilize shortened and lengthened VOTs, respectively, as cues in artificial-language segmentation. The phonetic-superiority hypothesis predicts that both groups should take advantage of the phonetic richness of longer VOTs (i.e., their enhanced auditory–perceptual robustness). Dutch and Korean listeners learned the words of an artificial language better when word-initial stops had longer VOTs than when they had shorter VOTs. It appears that language-specific phonological knowledge can be overridden by phonetic richness in processing an unfamiliar language. Listeners nonetheless performed better when the stimuli were based on the speech of their native languages, suggesting that the use of richer phonetic information was modulated by listeners' familiarity with the stimuli.

This paper discusses some current issues regarding how prosodic structure is manifested in fine-grained phonetic details, how prosodically-conditioned articulatory variation is explained in terms of speech dynamics, and how such phonetic manifestation of prosodic structure may be exploited in spoken word recognition. Prosodic structure is phonetically manifested in prosodically important landmark locations such as prosodic domain-final position, domain-initial position and stressed/accented syllables. It will be discussed how each of the prosodic landmarks engenders particular phonetic patterns, how articulatory variation in such locations are dynamically accounted for, and how prosodically-driven fine-grained phonetic detail is exploited by listeners in speech comprehension.

Prosodic structure in English speech is signalled, in part, by stronger articulation of consonants at the onset of intonational phrases (IPs) than of consonants that are IP-medial. In two cross-modal priming experiments, American English listeners heard sentences and decided whether visual letter strings, presented during the sentences, were real words. We manipulated sentence type (either no IP boundary or an IP boundary in a critical two-word sequence), splicing (whether the onset of the sequence’s second word was spliced from another token of that sentence or cross-spliced from a matched sentence with or without an IP boundary), and relatedness (whether the visual target was the first word in the spoken sequence). There was a relatedness effect on target responses for sentences with no IP boundary only when they were cross-spliced, that is, where splicing provided evidence of domain-initial strengthening. Listeners thus use this evidence when segmenting continuous speech.