Context effects on second-language learning of tonal contrasts.

Studies of lexical tone  learning generally focus on monosyllabic contexts, while reports of phonetic learning benefits associated with input variability are based largely on experienced learners. This study trained inexperienced learners on Mandarin tonal contrasts to test two hypotheses regarding the influence of context and variability on tone  learning. The first hypothesis was that increased phonetic variability of tones in disyllabic contexts makes initial tone  learning more challenging in disyllabic than monosyllabic words. The second hypothesis was that the learnability of a given tone varies across contexts due to differences in tonal variability. Results of a word learning experiment supported both hypotheses: tones were acquired less successfully in disyllables than in monosyllables, and the relative difficulty of disyllables was closely related to contextual tonal variability. These results indicate limited relevance of monosyllable-based data on Mandarin learning for the disyllabic majority of the Mandarin lexicon. Furthermore, in the short term, variability can diminish learning; its effects are not necessarily beneficial but dependent on acquisition stage and other learner characteristics. These findings thus highlight the importance of considering contextual variability and the interaction between variability and type of learner in the design, interpretation, and application of research on phonetic learning

Complexities of tonal realisation in a right-dominant Chinese Wu dialect - disyllabic tone sandhi in a speaker form Wencheng

An acoustically-based description is given of the isolation tones and right-dominant tone sandhi in disyllabic words of a male speaker of the Chinese Oūjiāng 甌江 Wú吳dialect of Wénchéng 文成. His seven isolation tones show typical Wu complexity, comprising two mid-level, two rising, two falling-rising and one depressed level pitch shapes. Typical too is his three-way voicing contrast in syllable-Onset stops. However, the typical Wu relationship between tonal register and phonemic Onset voicing is shown to be disrupted, Onset voicing no longer correlating with tonal pitch height. The word-final tones in sandhi are shown to be straightforwardly related, phonologically and phonetically, to the isolation tones, with biuniqueness preserved. The realization of the word-initial tones in sandhi, on the other hand, involves complex mergers conditioned by largely non-phonetic factors related to historical tone categories, resulting in five extra sandhi tones that do not occur in isolation. It is suggested that they not be related phonologically to the isolation tones. The historical implications of the patterns are also briefly explored

Final Devoicing: Principles and Parameters

This thesis addresses the problem of how to deal with the phonological event of final obstruent devoicing (FOD) in a theoretical framework based on principles and parameters rather than rules. The data used comes almost exclusively from German (Hochlautung). The first chapter presents the 'raw facts' of FOD. Its purpose is to provide an outline of the sort of data to be accounted for in the remainder of the thesis. Previous treatments of FOD in German are discussed and evaluated in the second chapter. All of them are shown to be associated with a number of problems, many of which are artifacts of inadequate theoretical frameworks. The third and fourth chapters address the questions of what FOD is and where it occurs. The proposed answer is couched in the framework of Government Phonology (Kaye, Lowenstamm & Vergnaud 1985, 1990), a phonological theory whose basic tenets are introduced in the course of the discussion. The conclusion drawn is that FOD is an instance of autosegmental licensing, where the laryngeal element L- requires licensing by a nuclear position with phonetic content. Chapter 5 explores the question of why FOD should exhibit the particular properties that it does. Both physical factors which are responsible for the general tendency of (final) obstruents to exhibit some degree of devoicing and the cognitive benefits which FOD can bring to speech recognition are investigated. The final chapter takes a new look at the concept of neutralisation in the context of FOD in German. It highlights Trubetzkoy's and Kiparsky's views of neutralisation and discusses some of the experimental work which has examined FOD as a putative process of neutralisation over the past decade. It is shown that apparent problems for phonological theory raised by the experimental studies can be resolved by Government Phonology

Altered Sensory Feedback in Speech

This chapter reviews the effects temporal, spectral and intensity perturbations to auditory and vibratory feedback have on fluent speakers and PWS. Early work on Delayed Auditory Feedback (DAF) with fluent speakers, showed that speech errors arise, speakers increase voice level, speech is slowed, medial vowels in syllables are elongated and pitch is monotone. It has been claimed that short-delay DAF produces effects on speech fluency, rate and naturalness that are as good as other forms of altered sensory feedback although this has been contested. Another alternative would be to reduce dosage by ramping intensity of altered auditory feedback down after a dysfluency provided speech is fluent and switch it to its full level when the next episode of stuttering occurs. Overall, temporal delays to speech feedback have a robust effect on fluent speakers and PWS. In fluent speakers, DAF induces a range of disruptions to speech

The use of acoustic cues in phonetic perception: Effects of spectral degradation, limited bandwidth and background noise

Hearing impairment, cochlear implantation, background noise and other auditory degradations result in the loss or distortion of sound information thought to be critical to speech perception. In many cases, listeners can still identify speech sounds despite degradations, but understanding of how this is accomplished is incomplete. Experiments presented here tested the hypothesis that listeners would utilize acoustic-phonetic cues differently if one or more cues were degraded by hearing impairment or simulated hearing impairment. Results supported this hypothesis for various listening conditions that are directly relevant for clinical populations. Analysis included mixed-effects logistic modeling of contributions of individual acoustic cues for various contrasts. Listeners with cochlear implants (CIs) or normal-hearing (NH) listeners in CI simulations showed increased use of acoustic cues in the temporal domain and decreased use of cues in the spectral domain for the tense/lax vowel contrast and the word-final fricative voicing contrast. For the word-initial stop voicing contrast, NH listeners made less use of voice-onset time and greater use of voice pitch in conditions that simulated high-frequency hearing impairment and/or masking noise; influence of these cues was further modulated by consonant place of articulation. A pair of experiments measured phonetic context effects for the "s/sh" contrast, replicating previously observed effects for NH listeners and generalizing them to CI listeners as well, despite known deficiencies in spectral resolution for CI listeners. For NH listeners in CI simulations, these context effects were absent or negligible. Audio-visual delivery of this experiment revealed enhanced influence of visual lip-rounding cues for CI listeners and NH listeners in CI simulations. Additionally, CI listeners demonstrated that visual cues to gender influence phonetic perception in a manner consistent with gender-related voice acoustics. All of these results suggest that listeners are able to accommodate challenging listening situations by capitalizing on the natural (multimodal) covariance in speech signals. Additionally, these results imply that there are potential differences in speech perception by NH listeners and listeners with hearing impairment that would be overlooked by traditional word recognition or consonant confusion matrix analysis

Stop Voicing and F0 Perturbation in Pahari

The present study has been carried out to investigate the perturbation effect of the voicing of initial stops on the fundamental frequency (F0) of the following vowels in Pahari. Results show that F0 values are significantly higher following voiceless unaspirated stops than voiced stops. F0 contours indicate an initially falling pattern for vowel [a:] after voiced and voiceless unaspirated stops. A rising pattern after voiced stops and a falling pattern after voiceless unaspirated stops is observed after [i:] and [u:]. These results match Umeda (1981) who found that F0 of a vowel following voiceless stops starts high and drops sharply, but when the vowel follows a voiced stop, F0 starts at a relatively low frequency followed by a gradual rise. The present data show no statistically significant difference between the F0 values of vowels with different places of articulation. Place of articulation is thus the least influencing factor

Automatic prosodic analysis for computer aided pronunciation teaching

Correct pronunciation of spoken language requires the appropriate modulation of acoustic characteristics of speech to convey linguistic information at a suprasegmental level. Such prosodic modulation is a key aspect of spoken language and is an important component of foreign language learning, for purposes of both comprehension and intelligibility. Computer aided pronunciation teaching involves automatic analysis of the speech of a non-native talker in order to provide a diagnosis of the learner's performance in comparison with the speech of a native talker. This thesis describes research undertaken to automatically analyse the prosodic aspects of speech for computer aided pronunciation teaching. It is necessary to describe the suprasegmental composition of a learner's speech in order to characterise significant deviations from a native-like prosody, and to offer some kind of corrective diagnosis. Phonological theories of prosody aim to describe the suprasegmental composition of speech..

At the edge of intonation: the interplay of utterance-final F0 movements and voiceless fricative sounds

The paper is concerned with the 'edge of intonation' in a twofold sense. It focuses on utterance-final F0 movements and crosses the traditional segment-prosody divide by investigating the interplay of F0 and voiceless fricatives in speech production. An experiment was performed for German with four types of voiceless fricatives: /f/, /s/, /ʃ/ and /x/. They were elicited with scripted dialogues in the contexts of terminal falling statement and high rising question intonations. Acoustic analyses show that fricatives concluding the high rising question intonations had higher mean centres of gravity (CoGs), larger CoG ranges and higher noise energy levels than fricatives concluding the terminal falling statement intonations. The different spectral-energy patterns are suitable to induce percepts of a high 'aperiodic pitch' at the end of the questions and of a low 'aperiodic pitch' at the end of the statements. The results are discussed with regard to the possible existence of 'segmental intonation' and its implication for F0 truncation and the segment-prosody dichotomy, in which segments are the alleged troublemakers for the production and perception of intonation

LANGUAGE CONTACT AND COVERT PROMINENCE IN THE SḤERĒT-JIBBĀLI LANGUAGE OF OMAN

This thesis reports on a phonetic production study, the results of which support the existence of a complex word-prosodic system for the Sḥerēt-Jibbāli language of Dhofar, Oman. In the language, stress seems to co-occur in some lexical items with a high tone. In the discussion, a mechanism for the emergence of this system is proposed as the reflex of a typological feature held in common with the related language, Soqotri, and as justification for an Eastern Modern South Arabian subgroup consisting of Sḥerēt-Jibbāli and Soqotri

Speech Compensation to Formant Perturbations in English and Vietnamese Talkers

The purpose of this experiment was to examine mechanisms underlying the auditory feedback system using Vietnamese and English talkers in response to feedback perturbations. F1 discrimination thresholds, vowel goodness ratings, and vowel category bounds for English /ɪ/ were determined. Vowel spaces were collected for both languages and auditory feedback of F1 was manipulated for English and Vietnamese vowels. Speech compensation during perturbed auditory feedback occurred in English and Vietnamese vowels suggesting that the underlying mechanisms are universal. However, there were differences in speech compensation for some vowel conditions, which may have occurred due to vowel location in each language group’s vowel space. Speech compensation may also be influenced by the perceptual boundaries of internal vowel categories where significant compensation may occur when feedback is non-prototypical to the target vowel category. Overall, these results suggest that the feedback system is sensitive to formant frequency changes that may have underlying phonological mediations