Voiceless Unaspirated Stop Research Articles

The Effect of Speaking Rate on the Voice Onset Time (VOT) of Bahdini Kurdish Stops

This research examines the effect of speaking rate on the voice onset time (VOT) of stop consonants in Bahdini Kurdish. 30 native speakers are chosen to take part in this study. VOT values are measured for all 10 Kurdish stop consonants produced by participants in carrier words in initial prevocalic onset position. The duration of the carrier word is also measured by using the Web MAUS service (Munich Automatic Segmentation), which is used for word duration measurements. Word duration measurements are compared to the VOT measurements to check whether they are both correlated or not based on laryngeal state and place of stop articulation (POA). Results reveal that there is an effect of speaking rate on VOT based on the three-way laryngeal contrast between the categories of voiced, voiceless aspirated and voiceless unaspirated stops in Bahdini Kurdish. VOT increases as word durations increase, which is inversely related to speaking rate. This means that VOT increases as speaking rate decreases. There is a systematic correlation between VOT and word duration based on different laryngeal states of voiced, voiceless aspirated and voiceless unaspirated stop categories. However, Place of Articulation (POA) does not show such an effect.

Phonetic structures of Washo

Washo is a severely moribund language spoken in several townships near the California-Nevada border southeast of Lake Tahoe. The Washo language is now used only by approximately 13–20 elderly speakers with very few fluent speakers under 60. Recordings were collected in Dresslerville, Nevada from two native speakers. Recordings collected by William Jacobsen Jr. in the 1960s provided additional data for comparison. Analysis showed that all the stops were either voiceless unaspirated, voiceless aspirated, or ejectivized. Vowel analyses showed the nature of the six long and short vowels. Special attention was paid to the nature of vowels and consonants in and around the stressed syllable. Post-tonic sibilants and sonorants are lengthened intervocalically even though consonantal length is not contrastive in Washo. Vowel length contrasts only in the stressed syllable. Stressed vowels are always long before an intervocalic voiceless unaspirated stop, but vocalic length contrast remains before aspirated stops and ejectives.

A study of vowel length in Thai

In Thai, vowel length is contrastive (e.g., [cìp] ‘‘to sip’’–[ciìp] ‘‘to pleat’’). The main cue to distinguish short-long vowels in Thai is vowel duration [Abramson, 1962]. However, in some literature, there are other cues for vowel length in Thai, such as final nasal duration. This paper was aimed to see how important vowel duration and final nasal duration are as perceptual cues for Thai listeners. A perceptual experiment was conducted. Eighteen (near-) minimal pairs of Thai words were used, consisting of initial voiceless unaspirated stop [p], nine pairs of Thai vowels, a final voiceless velar stop [k] or an alveolar final nasal [n]. Short vowels were lengthened and long vowels were shortened at 10–30-ms steps, using LPC analysis and resynthesis. The same procedure was done for short and long final nasals at 10-ms steps. All 1148 tokens were put into a Thai frame sentence and randomized. Forty native Thai listeners listened to these tokens and judged whether each token had a short or a long vowel. The results are that vowel duration is the main perceptual cue to distinguish short and long vowels in Thai.

The effect of perceptual training on the identification of a non‐native phoneme contrast and its relationship to the MMN auditory evoked potential

The mismatch negativity (MMN) auditory evoked potential reflects the detection of minimal stimulus differences at a pre‐attentive level. It has been reported that the MMN reflects acoustic, rather than phonetic processing of speech stimuli. The purpose of the present study was to examine the effects of perceptual training on (1) the behavioral ability of native speakers of American English to label a pair of Hindi stop consonants, and (2) the presence or absence of the MMN. Hindi voiceless unaspirated stop consonants contrasted by dental and retroflexplace of articulation ([t̪ versus [Ṡ]) were used. Prior to training, the MMN was present in 4 of 12 listeners and labeling ability was poor. Ten perceptual training sessions resulted in significant improvement in labeling ability. There was some generalization to a different voicing contrast (voiced unaspirated Hindi stop consonants [d̪] versus [ḍ]). There was also a significant increase in the number of listeners demonstrating an MMN in response to both contrasts after training. The group of listeners who had MMN responses after training also had significantly higher change scores from pre‐test to post‐test on the behavioral task. These results suggest that the MMN may have utility as an objective indicator of learning.

A study on the automatic recognition of voiceless unaspirated stops

This paper presents a method of feature extraction for the automatic recognition of voiceless unaspirated stop consonants in Mandarin speech. The features are derived from the spectrographic acoustic patterns of syllable-initial voiceless unaspirated stops /p,t,k/, which include the burst spectrum, the formant transition, and the voice onset time. A normalization process for the second and the third formants at the voice onset is proposed. Based on these derived features, Bayes classifiers and a layered neural net are applied to classify the places of articulation of these stop consonants. The experiments show that the derived features are robust and efficient for speaker-independent speech recognition, and the neural net is a preferable choice in the classification of these stops in multiple contexts.

Mechanisms of stop-consonant release for different places of articulation

The burst interval (i.e., VOT) following release of a voiceless unaspirated stop consonant has a duration that is somewhat longer for alveolars than for labials, and substantially longer for velars than for either. In the case of velars, the burst often consists of a sequence of two or more pulses. These facts may be explained in terms of a model which describes the effects of constriction geometry and articulatory kinematics, specific to different places of articulation, on aerodynamic events immediately following stop release. Calculations derived from this model suggest that Bernoulli forces may act on the surface of a compliant occluding articulator as closure is released. Presumably these forces cause a delay in the opening movement of the articulator, and a tendency for its surface to vibrate, that is greater for velars than for alveolars and labials. Measurements of VOT for stop consonants in different languages are described, with detailed data on the incidence of two or more release bursts and the temporal characteristics of those bursts. [Research supported by grants from NINCDS.]

Consonant types and tone in Siamese

This paper presents the results of an acoustical investigation of the effects of various consonant types on the tone of a following vowel in Siamese. In general, it is found that after voiceless obstruents, the fundamental frequency contour is relatively high and falling in transition to the following vowel; after voiced obstruents, the fundamental frequency contour is relatively low and rising (− falling). It is also found that the initial fundamental frequency value after the release of a voiceless unaspirated stop is higher than for a homorganic voiceless aspirated stop. For the voiceless aspirated stops, “plain” and “breathy” allophones are found that exhibit different effects on the tone of the following vowel. Implications for theories of pitch production and diachronic tonal development are discussed.

A Restriction on Grassmann's Law in Greek

It is well-known that Grassmann's law is restricted in its application in Greek vis-a-vis Sanskrit.1 In Greek, the rule applies generally to deaspirate an initial underlying aspirated stop in a reduplicating syllable: tithemi 'I place' < *thithemi, p6pheuga 'I have fled' < *phe-pheuga, k6khutai 'it has poured forth' < *khe-khutai, etc; but within a root it applies only to an initial dental and to /h/ from an underlying /s/: tr6pho 'I nourish' < *threpho (cf. thrMpso 'I shall nourish'), trikh6s 'hair, gen. sg.' < *thrikh6s (cf. thriks 'hair, nom. sg.'), 6kho 'I hold' < *hekho < *s6kh6 (cf. hckso 'I shall hold', eskhon 'I held'), etc. There are no cases in Greek in which a root-initial labial or velar voiceless unaspirated stop alternates with the corresponding aspirated stop.2 Therefore it may be presumed that diaspirate Indo-European roots were inherited by Greek with an initial voiceless unaspirated stop if and only if that stop was grave (labial or velar). For example, the Indo-European root *bheudh was inherited by Greek in the form peuth, since the initial labial of the root never appears as an aspirated stop in the paradigm of peithomai 'I ask'. Thus pezsomai 'I shall ask' is the attested form, not *phegsomai, which would be the expected form of the future if the underlying representation of the root were *pheuth. One possible interpretation of these facts is to say that at some stage in preGreek, root-initial aspirated (i.e. tense) grave stops in diaspirate roots were rephonemicized as unaspirated (i.e. lax) stops. Despite this apparent rephonemicization, however, and despite also the pre-Greek rephonemicization of the voiced aspirates in general as voiceless aspirates, Grassmann's Law can be stated for Greek in exactly the same form as for Sanskrit:3