Release Burst Research Articles

How Much Voicing in Voiced Geminates? The Laryngeal Voicing Profile of Polish Double Stops

Geminates (such as the double /k/ in Polish lekki “light”) form a group of consonants that are mainly characterized by longer durations than the corresponding singletons. Most of the research has concentrated on durational and spectral properties of geminates in contrast to singletons. Much less attention has been paid to the realization of the voicing contrast in geminates and whether it is differently implemented than in singletons. In the current study, we contribute to this research with the data from Polish stop geminates. To this end, a total of 49 native speakers of Polish produced all stop geminates and corresponding singletons in wordforms of the same phonological make-up. The measurements included closure duration, voicing ratio, duration and mean intensity of the release burst. The results showed that the voicing ratio was 0.69, classifying Polish stop geminates as mildly devoiced. There was a significant speaker-dependent variability in that some speakers devoiced all geminates, while others either partially devoiced or never devoiced. The analysis of interactions between geminates and singletons revealed that geminates cancelled voicing cues observed in singletons such as longer durations and lower intensity of the release burst. We discuss the current results in terms of voicing implementation in Polish and in relation to other geminating languages.

Flowable resin-based composites modified with chlorhexidine-loaded mesoporous silica nanoparticles induce superior antibiofilm properties

Clinical failure of dental resin-composite restorations is mainly due to bacterial-mediated secondary caries formation. Therefore, the development of a flowable resin-composite material having inherent antibacterial properties is crucial to enhance the durability of dental restorations. Herein, dental flowable resin-composite material was modified with chlorhexidine-loaded mesoporous silica nanoparticles (CHX-MSN) to induce in situ antibacterial properties against S. mutans. Mesoporous silica nanoparticles loaded with chlorhexidine (CHX-MSN) were formulated and characterized for drug-loading/encapsulation efficiency, morphology by electron microscopy, and infrared spectral analysis. CHX-MSN were incorporated into the flowable composite material at different concentrations of 1, 5, and 10% (w/w) and examined at two time points (baseline and 3 months in artificial saliva). The CHX-MSN modified composites exhibited an initial CHX release burst followed by a steady release up to 30 days. The antimicrobial efficacy of the modified composites was evaluated by crystal violet assay, MTT assay, and confocal laser scanning microscopy. In addition to measuring the degree of conversion and cytotoxicity, the mechanical properties were characterized by surface microhardness and flexural strength. The modified composites demonstrated a significant increase in antimicrobial properties compared to the unmodified control (p < 0.05) which is dependent on the concentration of the CHX-MSN nanoparticles. In addition, the modified composites possessed acceptable biocompatibility without adversely affecting mechanical properties and degree of conversion up to 5% addition of CHX-MSN nanoparticles. This study introduced a protocol to develop resin-based flowable dental composite material having superior antibacterial property against cariogenic biofilms aiming for enhancing clinical longevity of dental restorations.Graphical

Sex Differences in the Speech of Persons With and Without Parkinson's Disease.

Sex differences are apparent in the prevalence and the clinical presentation of Parkinson's disease (PD), but their effects on speech have been less studied. Speech acoustics of persons with (34 females and 34 males) and without (age- and sex-matched) PD were examined, assessing the effects of PD diagnosis and sex on ratings of dysarthria severity and acoustic measures of phonation (fundamental frequency standard deviation, smoothed cepstral peak prominence), speech rate (net syllables per second, percent pause ratio), and articulation (articulatory-acoustic vowel space, release burst precision). Most measures were affected by PD (dysarthria severity, fundamental frequency standard deviation) and sex (smoothed cepstral peak prominence, net syllables per second, percent pause ratio, articulatory-acoustic vowel space), but without interactions between them. Release burst precision was differentially affected by sex in PD. Relative to those without PD, persons with PD produced fewer plosives with a single burst: females more frequently produced multiple bursts, whereas males more frequently produced no burst at all. Most metrics did not indicate that speech production is differentially affected by sex in PD. Sex was, however, associated with disparate effects on release burst precision in PD, which deserves further study. https://doi.org/10.23641/asha.24388666.

Tannic Acid Interfacial Modification of Prochloraz Ethyl Cellulose Nanoparticles for Enhancing the Antimicrobial Effect and Biosafety of Fungicides.

With the poorly soluble and intrinsically unstable feature, prochloraz (Pro) was confronted with lower bioavailability in the crop defense against fungal erosion. Therefore, it was a challenging project to explore the innovative antifungal compound delivery system for improving bioavailability. The superior adhesive fungicide formulation was supposed to be an efficient pathway to enhance transmembrane permeability and biological activity. According to abundant phenolic hydroxyl groups, tannic acid (TA) was an ideal modified adhesive biomaterial to improve interfacial interactions. The fundamental purpose of this research was focused on the synergistic mechanism of TA-interfacial-modified Pro-ethyl cellulose (EC) nanoparticles for improving bioavailability and biosafety. In the stability test, TA-modified Pro-EC nanoparticles had the capacity to reduce Pro initial release burst, extending a persistent validity and improving anti-photodegradation property. The toxicity index of Pro-EC and Pro-EC-TA was approximately 2.93-fold and 4.96-fold that of Pro technical against Fusarium graminearum (F. graminearum), respectively. Compared with nonmodified EC nanoparticles, TA-modified EC nanoparticles obtained eminent transmembrane permeability and superior adherence ability to F. graminearum, for hydroxyl and carboxyl groups of TA to enhance interaction with target cell membranes. The contents of cellular reactive oxygen species induced by Pro-EC and Pro-EC-TA nanoparticles were about 2.31 times and 3.00 times that of the control check (CK), respectively. Compared to the CK group, the membrane potential and ergosterol values of F. graminearum treated with Pro-EC-TA nanoparticles were drastically reduced by 74.91 and 56.20%, respectively. In the biosafety assay, the maximum half-lethal concentration value of the TA-modified Pro-EC nanoparticles indicated that the acute toxicity of the Pro-EC-TA nanoparticles to adult zebrafish was approximately 8.34-fold reduced compared to that of the Pro technical. These findings demonstrated that the successful interfacial modification of Pro-EC nanoparticles with TA was a highly efficient, environmentally safe, and promising alternative for sustainable agricultural application, thus making the fungicide formulation process more simplified, easier fabrication, and lower cost.

Virus‐Engineered Microsol Electrospun Scaffold Promotes the Reprogramming of Fibroblasts to Neurons

AbstractLentiviral‐vector‐based therapies, widely used for treating various diseases, face limitations because of release burst, rapid clearance, and immune activation. Herein, a lentiviral vector delivery platform is proposed utilizing a virus‐engineered microsol electrospun scaffold. Identifying a remarkable upregulation of polypyrimidine tract binding protein1 (PTB) in spinal cord injury (SCI) rats, a scaffold is constructed comprising a hyaluronic acid (HA) core encapsulating brain‐derived neurotrophic factor (BDNF) and a polydopamine (PDA)‐modified linear poly‐l‐lactic acid (PLLA) shell, with shPTB lentiviral vectors (LV‐shPTB) grafted via PDA. In vitro, the LV‐shPTB achieves an infection efficiency of 70%, and the oriented scaffolds significantly reduce the expression of inflammatory factors, induce the reprogramming of fibroblasts into neurons, and sustain the release of BDNF for over 2 weeks. In vivo, the scaffolds provide physical support and neural guidance, as well as released BDNF and LV‐shPTB. LV‐shPTB delivery leads to the reprogramming of fibroblasts into neurons, and the sustained BDNF delivery maintains the neurons’ proliferation and growth, which further promotes the recovery of neurological function in SCI rats. These results demonstrate the potential application of virus‐engineered delivery platforms in SCI treatment and other medical fields.

Encapsulation of Carvacrol-Loaded Nanoemulsion Obtained Using Phase Inversion Composition Method in Alginate Beads and Polysaccharide-Coated Alginate Beads.

Nanoemulsions have been widely studied as lipophilic compound loading systems. A low-energy emulsification method, phase inversion composition (PIC), was used to prepare oil-in-water nanoemulsions in a carvacrol-coconut oil/Tween 80®-(linoleic acid-potassium linoleate)/water system. The phase behaviour of several emulsification paths was studied and related to the composition range in which small-sized stable nanoemulsions could be obtained. An experimental design was carried out to determine the best formulation in terms of size and stability. Nanoemulsions with a very small mean droplet diameter (16-20 nm) were obtained and successfully encapsulated to add carvacrol to foods as a natural antimicrobial and antioxidant agent. They were encapsulated into alginate beads by external gelation. In order to improve the carvacrol kinetics release, the beads were coated with two different biopolymers: chitosan and pullulan. All formulations were analysed with scanning electron microscopy to investigate the surface morphology. The release patterns at different pHs were evaluated. Different kinetics release models were fitted in order to study the release mechanisms affecting each formulation. Chitosan-coated beads avoided the initial release burst effect, improving the beads' structure and producing a Fickian release. At basic pH, the chitosan-coated beads collapsed and the pullulan-coated beads moderately improved the release pattern of the alginate beads. For acid and neutral pHs, the chitosan-coated beads presented more sustained release patterns.

Kinetics of carvacrol release from active paper packaging for fresh fruits and vegetables under conditions of open and closed package

The carvacrol release kinetics from active packaging (including carvacrol-βcyclodextrin inclusion complex) was studied under the following possible scenarios found in fresh produce packaging and marketing facilities: different storage temperatures (2, 8, 15 and 22 ºC), relative humidity (60% and 95% RH), as well as different packaging conditions (open or closed). Release kinetics for the closed and open packaging systems were described using first-order and n-order power law kinetics, respectively. Increasing temperature and RH enhanced the carvacrol release rate. The release rate (k) increased by 1.3–1.7-fold when the RH was augmented from 60% to 95%. An initial release burst effect was observed with the highest k rate (0.14/2.0 × 10−2 1/dayn) under open active packaging at 8/15 ºC (95% RH). In conclusion, the use of active packaging will ensure a proper essential oil release, with even a higher initial release (burst effect) in open packages, leading to a potential extension of the product shelf life.

Nanocarriers for drug-delivery systems using a ureido-derivatized polymer gatekeeper for temperature-controlled spatiotemporal on-off drug release.

Accidental chemotherapy extravasation exacerbates the side effects of anticancer drugs. Therefore, drug-delivery nanocarriers should be designed to avoid persistent drug release at off-target sites and promote burst drug release at on-target. Considering these requirements, poly(allylamine)-co-poly(allylurea) (PAU), a ureido-derivatized temperature responsive polymer with upper critical solution temperature (UCSTs), is an ideal material. This report describes the fabrication, characterization, and in vitro cellular toxicity of PAU polymer-grafted magnetic mesoporous silica nanoparticles as drug-delivery nanocarriers. A UCST of 43°C and an ultranarrow transition temperature range of 39-43°C was realized, ensuring that the nanocarriers suppressed undesirable leakage to below 10% of the drug loading for 8h in the absence of a thermal stimulus. A drug release burst of up to 75% of the drug loading was achieved within 30min after the stimulus, reducing the viability of the in vitro cancer cells to 12%. Therefore, the ureido-derivatized polymer is one of the most suitable gatekeepers for drug-delivery nanocarriers.

An ultrasound study of high vowel devoicing in Tokyo Japanese: Evidence for the vowel gesture retention

High vowels in Tokyo Japanese are typically devoiced between voiceless obstruents, but controversy remains over whether vowel gestures persist when devoiced or are instead deleted. A previous ultrasound study (Iwasaki et al., 2020) showed that the lingual articulation of the release burst of /kV/ differs by vowel context even when the vowels are devoiced. This study uses tongue surface contours derived from midsagittal ultrasound images to investigate the effects of vowel devoicing on changes in quantified tongue shape over time. Native speakers of Tokyo Japanese produced word pairs (/C1VC2e/) that contrasted in the voicing of V, which was either /i/ or /u/. Tongue shape was characterized by Fourier transforming tangent angles along each contour (Dawson et al., 2016). Time-normalized trajectories over the /C1VC2e/ sequence were compared by vowel context (/i/ versus /u/) and voicing environment (devoiced versus voiced). Preliminary results show that the real component of the first Fourier coefficient is sensitive todetecting evolving shape differences between the two vowel contexts over the sequence, not just when the vowels are voiced, but also when they are devoiced. Based on these results, the high vowel contrast persists even in the devoiced environment, suggesting that devoiced vowels are not deleted.

The acoustics of word-initial and word-internal voiced stops in Somali

This article seeks to determine the acoustic correlates of gemination in Standard Somali (Afroasiatic, Cushitic), in particular whether closure duration is the primary acoustic correlate distinguishing singleton and geminate stops, with immediate consequences for the analysis of word-initial strengthening. We provide an acoustic analysis of word-initial and word-internal voiced singletons as well as of their geminate counterparts on the basis of a production experiment conducted with four native speakers. Three temporal and four non-temporal acoustic properties of /b d ɡ/ and /bb dd ɡɡ/ are examined and systematically compared (closure duration, release burst duration, vowel duration; and closure amplitude, release amplitude, presence of a release burst, (de)voicing). We argue that the opposition between singleton and geminate voiced stops is primarily realized as the manner contrast approximant [β̞ ð̞ ɣ̞] vs. stop [b d ɡ]. Word-initially, Somali exhibits various peculiarities that are reminiscent of the cross-linguistically attested phenomenon of domain-initial strengthening. This article provides the first study of this phenomenon in Somali. We establish that word-initial /b d ɡ/ and word-medial /bb dd ɡɡ/ share the same closure duration, release burst duration, and vowel duration within the Prosodic Word. They also have a similar closure amplitude, and voicing properties. Moreover, the acoustic properties of word-initial /b d ɡ/ remain constant, and do not depend on their position in the prosodic hierarchy. On the basis of these results, the article also aims at providing new insights in the phonological representation of Somali geminates and word boundaries, and thus contributes to the understanding of word-initial strengthening in Somali.

Unreleased Bursts of Final Stops in English Words as Pronounced by Native Speakers of Javanese from Yogyakarta

This research aims to describe how native speakers of Javanese from Yogyakarta realize final stops in English words, understand how often they pronounce final stops in English words with audible release burst, and examine whether release burst in final stops is a feature of Yogyakartan Javanese accent of English, based on their occurrence frequency. 20 native Javanese speakers from Yogyakarta were asked to pronounce 24 English words ending in stops: /p/, /t/, /k/, /b/, /d/, and /g/. The recordings were then analyzed and compared against recordings of the words produced by native English speakers using Praat to identify the release bursts. The finding shows that release burst can be found in 7 out of 80 (8.75%) recordings of words ending in final /p/, 8 out of 80 (10%) recordings of words ending in final /t/, 15 out of 80 (18.75%) recordings of words ending in final /k/, 10 out of 80 (12.5%) recordings of words ending in final /b/, 9 out of 80 (11.25%) recordings of words ending in final /d/, and 16 out of 80 (20%) recordings of words ending in final /g/. In total, 165 out of 480 (13.54%) recordings contain release bursts in the final stop.

Unreleased Bursts of Final Stops in English Words as Pronounced by Native Speakers of Javanese from Yogyakarta

This research aims to describe how native speakers of Javanese from Yogyakarta realize final stops in English words, understand how often they pronounce final stops in English words with audible release burst, and examine whether release burst in final stops is a feature of Yogyakartan Javanese accent of English, based on their occurrence frequency. 20 native Javanese speakers from Yogyakarta were asked to pronounce 24 English words ending in stops: /p/, /t/, /k/, /b/, /d/, and /g/. The recordings were then analyzed and compared against recordings of the words produced by native English speakers using Praat to identify the release bursts. The finding shows that release burst can be found in 7 out of 80 (8.75%) recordings of words ending in final /p/, 8 out of 80 (10%) recordings of words ending in final /t/, 15 out of 80 (18.75%) recordings of words ending in final /k/, 10 out of 80 (12.5%) recordings of words ending in final /b/, 9 out of 80 (11.25%) recordings of words ending in final /d/, and 16 out of 80 (20%) recordings of words ending in final /g/. In total, 165 out of 480 (13.54%) recordings contain release bursts in the final stop.

Realisation of Voice Onset Time (VOT) and Its Implication on Voicing of English (RP) Stops in Ghanaian English (GhE)

There has been a general perception that the English voiced stops /b, d, g/ before and after a pause or silence are more often confused with the initial voiceless stops /p, t, k/. Thus, in distinguishing the two, listeners most often depend on the onset of voicing of the following segments. Voice onset time, therefore, serves as a significant cue in distinguishing English voiced stops from their voiceless counterparts. Interestingly, voiceless stops in many Ghanaian indigenous languages appear to be weakly aspirated; they are perceived to be made with a very short voice onset time. However, listeners are able to distinguish the voiceless stops from their voiced counterparts. What this study sought to do was to investigate the production of English initial voiceless stops, /p, t, k/ in Ghanaian English. Specifically, it sought to examine the voice onset time of the stops, and whether listeners are able to distinguish English stops made with weak aspiration from the voiced stops before and after a pause. The study used 112 Ghanaian speakers, 76 for a production test; they produced 21 tokens of the stops in a /p/-, /t/- and /k/- initial words, and 36 for a perception test; they listened to words produced with voiced stops in a /b-b/, /d-d/ and /g-g/ environments. The study has revealed that for all the voiceless stops, voicing for the following segments began after the stops were released, and there was no pre-voicing or voice lead. However, for some of the stops, voicing coincided with the release, while for some voicing began after an appreciable amount of time after the release burst. The length of the VOT was found to have been affected by place of articulation and vowel contexts. However, speaker sex seems to have no effect on the length of the VOT. It is clear that Ghanaian speakers of English would have no difficulty distinguishing weakly aspirated stops from voiced stops before and after a pause. Also, understanding words having the initial voiced stops before and after a pause and weakly aspirated stops produced by Ghanaians will not be a problem to listeners.

Acoustic Features of Burst Release: A Study of Welsh Plosives

The aim of this paper is to analyse the centre of gravity (COG) of release bursts in Welsh plosives in order to assess their importance in distinguishing between /p, t, k/ (here termed fortis) and /b, d, g/ (here termed lenis). The COG of a release burst appears to be particularly interesting as (i) it has not yet been studied extensively in the phonetic scientific literature on Welsh plosives (see for instance Ball, Ball and Williams, Jones, Morris and Hejná), and (ii) using the COG variable to distinguish between stops is not very common, as it is normally used to differentiate between places of articulation in fricatives. To achieve the aforementioned goals, the authors, inspired by a study of American English plosives conducted by Chodroff and Wilson, measured the COG of bursts in word-initial /p, b, t, d, k, g/.

Preparation of ropivacaine-loaded mesoporous bioactive glass microspheres and evaluation of their efficacy for sciatic nerve block

Local anesthetics are mainly used for regional anesthesia and analgesia. However, the duration of action is limited in clinical applications. In the present study, we developed a ropivacaine (RPC)-loaded mesoporous bioactive glass (MBG) microspheres for an extended analgesic duration. First, MBG microspheres were prepared using a template synthesis method. RPC was then loaded into the MBG microspheres through immersion, followed by centrifugation and drying. Finally, the RPC-loaded MBG microspheres were coated with a polylactic acid-b-polyethylene glycol (PLA-PEG) copolymer to obtain RPC-MBG composite microspheres (RPC microspheres). The particle size and zeta potential of the RPC microspheres were 192.3 ± 9.6 nm and −35.6 ± 3.5 mV, with entrapment efficiency (EE) of 88.2 ± 3.2% and low cytotoxicity. In vitro, the release profile of RPC microspheres exhibited a biphasic pattern: an initial release burst within the first hour, followed by subsequent slower and sustained release. After performing a single-shot sciatic nerve block, a fast the anesthetic effect and prolonged analgesic effect were achieved. Given the low cytotoxicity and sustained release, the RPC microspheres developed in this study could be used as a long-acting local anesthetic.

Pharmacokinetics of Exenatide in nonhuman primates following its administration in the form of sustained-release PT320 and Bydureon

The time-dependent (30 min - day 84) plasma profile of PT320, a sustained-release (SR)-Exenatide formulation under clinical development for treatment of neurodegenerative disorders, was evaluated in nonhuman primates after a single subcutaneous dose and was compared to Bydureon. Exenatide release from PT320 exhibited a triphasic pharmacokinetic profile. An initial peak occurred at 3 hr post-administration, a secondary peak at 5 days, and achievement of Exenatide steady-state plasma levels from day 10–28. Systemic exposure increased across PT320 doses, and Exenatide levels were maintained above the therapeutic threshold prior to achieving a steady-state. In contrast, Exenatide release from Bydureon exhibited a biphasic profile, with an initial plasma peak at 3 hr, followed by a rapid decline to a sub-therapeutic concentration, and a gradual elevation to provide a steady-state from day 35–49. Exenatide total exposure, evaluated from the area under the time-dependent Exenatide concentration curve, was similar for equivalent doses of PT320 and Bydureon. The former, however, reached and maintained steady-state plasma Exenatide levels more rapidly, without dipping to a sub-therapeutic concentration. Both SR-Exenatide formulations proved well-tolerated and, following a well-regulated initial release burst, generated steady-state plasma levels of Exenatide, but with PT320 producing continuous therapeutic Exenatide levels and more rapidly reaching a steady-state.

Polyethylene Oxide Functionalized Mesoporous Silica Nanoparticles for pH- Responsive Quercetin Release

Abstract Mesoporous silica nanoparticles (MSN) known as one of the best material of nanotechnology for drug delivery application with their unique properties that suit a therapeutic field. However, the major challenge for nanotechnology is premature release before reached to target cell. Thus, by incorporation of polyethylene oxide (PEO) in MSN loaded with quercetin (QT), the release profile properties can be controlled by meeting to specify pH value of cancer cell, in form of MSN/QT/PEO membrane. The samples have been characterized using FTIR, XRD, TEM, and FESEM-EDX while the adsorption of QT was carried out for 10 hours contact time which results in 80%. Based on the characterization, MSN specified a relatively higher number of pores with larger diameters while MSN/QT/PEO membrane produced the new functional group between MSN/QT with the PEO which indicate to the stronger bonded and pH-responsive at lower pH value. The image of the structure clearly differentiates the composition ratio of MSN/QT/PEO membrane in ratio of 1:0.02:4 respectively and the fabrication using a drying method for 3 days in ambient condition. The release profile had been analyzed in pH 7 and pH 4 at 37°C, and the result shows that MSN/QT released maximum rate of QT within 4 hours for pH 7 while there was negligible release of QT (less than 1%) for MSN/QT/PEO membrane meanwhile at pH 4, MSN profile release burst within early third hours in 50% while the sustained and slowly released was shown by MSN/QT/PEO membrane up to 20 hours. From this study, efficient encapsulation of drug molecules can be suggested as an alternative to the drug delivery application

Visual-Tactile Speech Perception and the Autism Quotient.

Multisensory information is integrated asymmetrically in speech perception: An audio signal can follow video by 240ms, but can precede video by only 60ms, without disrupting the sense of synchronicity (Munhall et al., 1996). Similarly, air flow can follow either audio (Gick et al., 2010) or video (Bicevskis et al., 2016) by a much larger margin than it can precede either while remaining perceptually synchronous. These asymmetric windows of integration have been attributed to the physical properties of the signals; light travels faster than sound (Munhall et al., 1996), and sound travels faster than air flow (Gick et al., 2010). Perceptual windows of integration narrow during development (Hillock-Dunn and Wallace, 2012), but remain wider among people with autism (Wallace and Stevenson, 2014). Here we show that, even among neurotypical adult perceivers, visual-tactile windows of integration are wider and flatter the higher the participant’s Autism Quotient (AQ) (Baron-Cohen et al., 2001), a self-report measure of autistic traits. As “pa” is produced with a tiny burst of aspiration (Derrick et al., 2009), we applied light and inaudible air puffs to participants’ necks while they watched silent videos of a person saying “ba” or “pa,” with puffs presented both synchronously and at varying degrees of asynchrony relative to the recorded plosive release burst, which itself is time-aligned to visible lip opening. All syllables seen along with cutaneous air puffs were more likely to be perceived as “pa.” Syllables were perceived as “pa” most often when the air puff occurred 50–100ms after lip opening, with decaying probability as asynchrony increased. Integration was less dependent on time-alignment the higher the participant’s AQ. Perceivers integrate event-relevant tactile information in visual speech perception with greater reliance upon event-related accuracy the more they self-describe as neurotypical, supporting the Happé and Frith (2006) weak coherence account of autism spectrum disorder (ASD).

L1 Interference in Koreans' Perception of Released Word-final Stops in English

This study investigated L1 interference in the perception of released word-final stops in English by performing perception experiments on Korean and English listeners. Stimuli with conflicting cues were used in experiments in which the ‘long CV’ and the ‘short vowel CV’ were rejoined with six silent closure duration intervals and two release bursts of [g] and two release bursts of [k]. The perception results show that Korean listeners perceived significantly more [k] compared to English listeners when ‘k’ release was attached to a ‘long CV.’ We suggest that this is due to different phonological systems in Korean and English. In Korean, a released stop occurs only in the onset position in which the VOT and the stop closure duration are important acoustic cues for the identity of a stop. Thus, the English coda [k] with voiceless release burst could be perceived as an onset with long VOT, namely [k], by Korean listeners. In contrast, English listeners mostly perceived a voiced stop due to the long preceding vowel (cf. Raphael, 1972). With the stimuli of ‘short CV’ with ‘g’ release, Korean listeners perceived significantly more [g] than NE listeners did. English coda [g] with a voiced release may be perceived as an onset [g] with a short VOT by Korean listeners. In contrast, English listeners perceived a voiceless stop [k] due to the preceding short vowel. This paper also showed that Korean listeners would perceive finer distinctions than two levels of release, ‘g’ release and ‘k’ release.

On the relation between speech perception and loanword adaptation

Loanword adaptation has been claimed to provide a unique window onto the relation between speech perception and the phonological grammar. This paper focuses on whether the ‘illusory vowel’ effect—in which the presence/absence of a vowel is poorly discriminated within an illicit cluster—is sufficient to explain why vowel epenthesis is the preferred repair for medial clusters in Korean loanword adaptation. A cross-linguistic discrimination experiment revealed a causative role of the stop release burst (or other audible frication noise) in the perception of an illusory vowel; in some cases, perception alone explains vowel epenthesis in loanword adaptation. A follow-up, identification experiment showed that Koreans’ perceptual similarity judgements do not match up with the adaptation pattern for stop-nasal clusters (e.g. pakna), although they do for fricative-stop and stop-stop clusters (e.g. paska, pakta). This finding is problematic for a purely perceptual account of loanword adaptation. The paper sketches a Bayesian account of Korean speech perception that integrates top-down phonotactic likelihood and bottom-up acoustic match and is able to explain the experimental results. It closes with some speculation on the role of the Preservation Principle versus perception in loanword adaptation.