Geminate Stop Research Articles

Effects of vowel devoicing on the closure duration of japanese singleton and geminate stops

Closure duration is an acoustic variable known to distinguish Japanese singleton and geminate stops. It has been established that the closure duration varies with speaking rate. However, it has not been determined whether the closure duration is affected by devoicing of vowels preceding or following the stops. To determine the effects of such vowel devoicing, a production experiment was conducted with 20 Japanese native speakers. They pronounced four minimal pairs of onomatopoeic words contrasting singleton and geminate stops at various speaking rates. Devoiced vowels were found to affect closure duration preceding the stops, such that the closure with a devoiced preceding vowel is longer than that with a voiced preceding vowel, although the effect is weak for singleton stops. However, devoiced vowels do not affect the duration when they follow stops. These results suggest that vowel devoicing interacts with an acoustic variable of stop consonants, especially in the case of geminate stop.

Thai Speakers’ Mispronunciation of Japanese Singleton and Geminate Stops

Thai Speakers’ Mispronunciation of Japanese Singleton and Geminate Stops

促音/tt/の知覚 : アクセント型と促音・非促音語の音響的特徴による違い

促音/tt/の知覚 : アクセント型と促音・非促音語の音響的特徴による違い

Japanese singleton and geminate stops mispronounced by non-native speakers

Non-native Japanese speakers often mispronounce Japanese singleton and geminate stops. However, it has been unclear how durations of speech segments in their mispronunciation differ from those of correct pronunciation by native Japanese speakers. This study analyzed mispronunciation of singleton and geminate stops by non-native speakers (8 English, 12 French, and 10 each of Korean, Taiwanese, Thai, and Vietnamese). Non-native speakers' mispronunciations were identified based on 10 native Japanese speakers' production boundary between singleton and geminate stops. It was revealed that when non-native speakers mispronounce a singleton stop as a geminate stop, stop closure is longer whereas its previous mora is shorter than in native speakers' correct pronunciation. Meanwhile, when non-native speakers mispronounce a geminate stop as a singleton stop, stop closure is shorter whereas its following mora is longer. These findings indicate that non-native speakers’ mispronunciations are caused not only by the dur...

Discriminant variables for plosive- and fricative-type single and geminate stops in Japanese

Previous studies suggested that a plosive-type geminate stop in Japanese is discriminated from a single stop with variables of stop closure duration and subword duration that spans from the mora preceding the geminate stop to the vowel following the stop. However, this suggestion does not apply to a fricative-type geminate stop that does not have a stop closure. To overcome this problem, this study proposes Inter-Vowel Interval (IVI) and Successive Vowel Interval (SVI) as discriminant variables. IVI is the duration between the end of the vowel preceding the stop and the beginning of the vowel following the stop. SVI is the duration between the beginning of the vowel preceding the stop and the end of the vowel following the stop. When discriminant analysis was conducted between single and geminate stops of plosive and fricative types using IVI and SVI as independent variables, the discriminant ratio was very high (99.5%, n = 368). This result indicates that IVI and SVI are the general variables that represent acoustic features distinguishing Japanese single and geminate stops of both plosive and fricative types. [This study was supported by JSPS KAKENHI Grant Numbers 24652087, 25284080, 26370464 and by Aichi-Shukutoku University Cooperative Research Grant 2013-2014.]

Individual differences in cue weights are stable across time: The case of Japanese stop lengths

Speech categories are defined by multiple acoustic dimensions, and listeners give differential weighting to dimensions in phonetic categorization. The informativeness (predictive strength) of dimensions for categorization is considered an important factor in determining perceptual weighting. However, it is unknown how the perceptual system weighs acoustic dimensions with similar informativeness. This study investigates perceptual weighting of two acoustic dimensions with similar informativeness, exploiting the absolute and relative durations that are nearly equivalent in signaling Japanese singleton and geminate stop categories. In the perception experiments, listeners showed strong individual differences in their perceptual weighting of absolute and relative durations. Furthermore, these individual patterns were stable over repeated testing across as long as 2 months and were resistant to perturbation through short-term manipulation of speech input. Listeners own speech productions were not predictive of how they weighted relative and absolute duration. Despite the theoretical advantage of relative (as opposed to absolute) duration cues across contexts, relative cues are not utilized by all listeners. Moreover, examination of individual differences in cue weighting is a useful tool in exposing the complex relationship between perceptual cue weighting and language regularities.

Production of single and geminate stops in Japanese three- and four-mora words

This study examined the durational structure of single and geminate stop distinction produced in three- and four-mora words of Japanese, (C(1))V(1)(C(2))C(2)V(2)X [(C(2))C(2) = the contrasting consonants; X = a CV mora, the moraic nasal, or a long vowel as part of V(2)]. The questions addressed were how factors such as speaking rate, segmental variability, and moraic composition of words affected the stop quantity distinction in words longer than well-studied disyllabic words, and whether there exists an invariant parameter that classified these two stop categories. Results showed that all of those factors systematically affected the duration of the contrasting stop closure, the unit of [(C(1))V(1)(C(2))C(2)V(2)], and the entire three- and four-mora words. However, the durational units of moras and words were well-structured, and the ratio of the contrasting stop closure to the [(C(1))V(1)(C(2))C(2)V(2)] unit, as well as the ratio of the closure to the entire word, were found to be invariant in indicating the stop quantity distinction. These results support the theory of relational acoustic invariance [Pickett et al., Phonetica 56, 135-157 (1999)] on the part of production. Furthermore, the results provide insight into different versions of Japanese mora hypothesis [Han, The Study of Sounds 10, 65-80 (1962); Port et al., J. Acoust. Soc. Am. 81(5), 1574-1585 (1987)], which have been under debate for five decades.

Vowel onset as a rhythmic marker in Japanese single and geminate stop distinctions

Hirata and Whiton (2005) found that the durational ratio of stop closure to a disyllabic word was the best parameter to distinguish singleton and geminate stops in spoken Japanese. However, given that vowel onset has perceptual and psychoacoustic importance as a temporal marker (Kato et al., 2003), the best unit may be from the first vowel onset of the target word to that of the following word in a carrier sentence (= Vword). In this study, 36 target disyllabic pairs including singletons and geminates (e.g. [buka] and [buk:a]) were embedded in the sentence [sokowa ____to jomimasu], spoken by four native Japanese speakers at three rates (Hirata and Whiton, 2005). The duration of Vword (e.g. the beginning of `u' in [buka] to the beginning of `o' in [to]) and of Vc(c) (e.g. `uk' from [buka] and `ukk' from [buk:a]) were measured, and the Vc(c)/Vword ratio was calculated. We examined how accurately this ratio classified singleton and geminate tokens across all rates and speakers. The classification accuracy was found to be 97.3-98.0%. This indicates that the duration of Vc(c) relative to Vword is a stable parameter for quantity distinction, and that the Vc(c) unit may constitute a meaningful rhythmic marker in production.

Relational Timing in the Production and Perception of Japanese Singleton and Geminate Stops

This work examines the production and perception of the Japanese singleton versus geminate stop contrast in order to investigate properties that distinguish the contrast in the face of variability due to speech rate. The acoustic study found two local relational durations, the ratio of the stop to the preceding mora and the ratio of the stop to the following vowel, to be stable across speaking rates and to accurately classify singleton and geminate productions. However, the subsequent perception study demonstrated an influential role of the preceding mora duration and a marginal role of the following vowel duration on listeners’ categorization. These results demonstrate that Japanese listeners can take advantage of relative duration in the perception of the stop length contrast, and that relative strength of simultaneously available acoustic cues does not necessarily translate into equal perceptual importance.

Acoustic covariants of length contrast in Japanese stops

This study explores acoustic correlates to the singleton vs. geminate stop length contrast in Japanese. The proposal examined is that multiple acoustic features covary with the stop length distinction and that these features are available in the signal as potential secondary cues. The results support the proposal, revealing the presence of several acoustic features covarying with the singleton vs. geminate contrast in both durational and non-durational domains. Specifically, the preceding vowel is longer, the following vowel is shorter, there are greater fundamental frequency and intensity changes from the preceding to the following vowel, and there is evidence of more creakiness in voice quality for geminate than singleton consonants. It is also demonstrated that the vowel durations, as well as fundamental frequency and intensity changes have fairly strong categorization power.

Perception of a Japanese Geminate Stop in Korean Learners: the Effect of Pitch Type and Phonetic Characteristics of a Consonant in a Preceding Syllable following the t-closure

Perception of a Japanese Geminate Stop in Korean Learners: the Effect of Pitch Type and Phonetic Characteristics of a Consonant in a Preceding Syllable following the t-closure

An acoustic and perceptual investigation of the geminate and singleton stop contrast in Japanese

Segmental durations are known to be heavily influenced by changes in speech rate such that the durations of members of two contrasting length categories may overlap [Pickett et al. ‘‘Effects of speaking rate on singleton/geminate contrast in Italian,’’ Phonetica 56, 135–157 (1999); Hirata & Whiton, ‘‘Relational acoustic invariance in the single/geminate stop distinction in Japanese,’’ J. Acoust. Soc. Am. 117, 2569 (2005)]. Given this, questions arise as to how category distinction is achieved for contrasts signaled by differences in segmental duration. This study investigates the question by examining the production and perception of the Japanese singleton versus geminate stop contrast by adult native speakers. Six native Japanese speakers produced disyllabic words with medial singleton and geminate stops at three speaking rates. Duration of stop closure and a number of relational timings between the closure duration and other segments were examined as potential rate-independent measures distinguishing the two categories. The ratios of stop closure to the preceding mora as well as stop closure to the following vowel remained stable across speaking rate and accurately classified naturally produced tokens. Ten native Japanese listeners participated in an identification task to examine the perceptual relevance of these relational timings. The results indicated an influential role of preceding mora duration and a small role of following vowel duration. The results also suggested that nondurational factor(s) influence perception of the stop length contrast.

Perception of a Japanese Geminate Stop: the Effect of the Duration of the Preceding/Following Vowel

Perception of a Japanese Geminate Stop: the Effect of the Duration of the Preceding/Following Vowel

Developmental dyslexia and discrimination in speech perception: A dynamic model study

At the behavioral level one of the primary disturbances involved in congenital dyslexia concerns phonological processing. At the neuroarchitectural level autopsies have revealed ectopies, e.g., a reduced number of neurons in the upper layers of the cortex and an increased number in the lower ones. In dynamic models of interacting neuronal populations the behavioral level can be related to the neurophysiological level. In this study an attempt is made to do so at the cortical level. The first focus of this model study are the results of a Finnish experiment assessing geminate stop perception in quasi speech stimuli by 6 month old infants using a head turning paradigm and evoked potentials. The second focus of this study are the results of a Dutch experiment assessing discrimination of transients in speech stimuli, by adult dyslexics and controls and 2 month old infants. There appears to be a difference in the phonemic perceptual boundaries of children at genetic risk for dyslexia and control children as revealed in the Finnish study. Assuming a lowered neuronal density in the ‘dyslexic’ model, reflecting ectopies, it may be postulated that less neuronal surface is available for synaptic connections resulting in a lowered synaptic density and thus a lowered amount of available neurotransmitter. A lowered synaptic density also implies a reduced amount of membrane surface available for neurotransmitter metabolism. By assuming both, a reduced upper bound of neurotransmitter and a reduced metabolic transmitter rate in the dynamic model, the Finnish experimental results can be approximated closely. This applies both to data from behavioral head turning and that of the evoked potential study. In the Dutch study adult dyslexics show poor performance in discriminating transients in the speech signal compared to the controls. The same stimuli were used in a a study comparing infants from dyslexic families and controls. Using the same transmitter parameters as in modeling the results of the Finnish study, also in this case the experimental results for adults and infants can be approximated closely. Simulation of behavioral and pharmaceutical interventions with the model provide predictions which can be put to the test in experiments.

The Effect of Kana Literacy Acquisition on the Speech Segmentation Unit Used by Japanese Young Children

Three experiments were undertaken to investigate whether young children's segmentation units would change as they learned to read kana letters, which represent morae (subsyllabic rhythmic units). The first 2 experiments used a vocal–motor segmentation task to examine whether 4- to 6-year-olds preferred to segment spoken words containing the special syllables CVN, CVQ, or CV: into syllables or into morae. The third experiment used a target monitoring task for CVN to examine whether children's detection of the target syllable in a series of words would vary depending on the moraic constitution of the target and the moraic–syllabic status of the word initial in which the target was embedded. Results indicated that the children's conscious segmentation of words, except for those having a geminate stop consonant (CVQ), developed from being a mixture of syllable- and mora-based to being predominantly mora-based as they learned to read kana letters. The tendency toward mora-based segmentation was also found in the target monitoring task, which required segmentation at a less conscious level.

Acoustic manifestations of mora timing in Japanese

Segment durations in 20 minimal-paired words in Japanese were examined to identify regular patterns of acoustic manifestations of mora timing in Japanese. The results indicate that segments consistently stretch or compress, providing temporal compensation within a mora and between moras, to attain targeted length at the word level. A segment is 11% longer in the pre-geminate-stop position than in the pre-single-stop position; in the word final position, a segment is 9% shorter following a geminate stop than a segment following a single stop; and [t] in the same phonotactic environment shows varied durations according to different moraic conditions. Fricatives followed by a devoiced vowel are considerably longer than any other inherently long, nonmoraic segments, and are comparable to moraic segments and the average mora duration. Syllable durations are not isochronous, varying by as much as 50%. The word duration is affected more by the number of component sounds and their inherent durations in two-mora than in three-or four-mora words. When the word durations are converted into ratios, they are markedly similar to the mora values. The results suggest a timing control mechanism adjusting segments to obtain targeted word durations. These phenomena describe mora timing in Japanese.

Acoustic properties of geminate consonants

It is generally assumed in informal descriptions that what distinguishes geminate from nongeminate consonants is duration of articulation. This has not, however, been demonstrated instrumentally, nor are informal descriptions precise about what should be measured. To study the acoustic features of geminates, we investigated geminate stops in Turkish, comparing geminate and nongeminate stop consonants in similar environments. We measured the duration from the beginning of the preceding vowel to the beginning of the consonant closure, the pause duration from the end of the preceding vowel to the beginning of the following consonant, the duration of consonant closure, and the ratio of the rms energy at the onset of the consonant to that of the following vowel. The only significant difference was the duration of the pause. To investigate the perceptual salience of this feature, we took 20 minimal pairs of geminates and nongeminates, cross spliced the pause, and presented a randomized set of words to native speakers of Turkish, who wrote down what they heard. The pause was found to be a significant cue in discriminating between geminate and nongeminate consonants.

Proto-Algonquian Consonant Clusters in Delaware

1. Proto-Algonquian h and n precede p, t, c, k, s, 2, 0, 1, while ? precedes all these except p and k; c and x precede only p and k, while S precedes not only p and k but also t; and C is prior member to k alone. As second members in clusters, t, 1, 0 behave morphophonemically like the corresponding single consonants. So also in F C M 01 and D, t reflects the old alternation to c before high front vowels; however, in D 1 (reflex of PA 1 and 0) has lost the old habit of alternation with S both as a single consonant and as the second member of a cluster (see 5 and 6.4 below). 2. The PA sequence h-stop remains in F C M and appears as geminate stop in O. But more than one reflex is found in D.