Language and Speech最新文献

The primary purpose of this research report was to investigate the relationships between acoustic characteristics and perceived intelligibility for native Japanese speakers' productions of American English liquids. This report was based on a reanalysis of intelligibility scores and acoustic analyses that were reported in two previous studies. We examined which acoustic parameters were associated with higher perceived intelligibility scores for their productions of /l/ and /ɹ/ in American English, and whether Japanese speakers' productions of the two liquids were acoustically differentiated from each other. Results demonstrated that the second formant (F2) was strongly correlated with the perceived intelligibility scores for the Japanese adults' productions. Results also demonstrated that the Japanese adults' and children's productions of /l/ and /ɹ/ were indeed differentiated by some acoustic parameters including the third formant (F3). In addition, some changes occurred in the Japanese children's productions over the course of 1 year. Overall, the present report shows that Japanese speakers of American English may be making a distinction between /l/ and /ɹ/ in production, although the distinctions are made in a different way compared with native English speakers' productions. These findings have implications for setting realistic goals for improving intelligibility of English /l/ and /ɹ/ for Japanese speakers, as well as theoretical advancement of second-language speech learning.

The "hyper-variation" present in rhotic sounds makes them particularly apt for sociophonetic research. This paper investigates the variable realization of the voiced alveolar-trill phoneme /r/ through an acoustic analysis of unscripted speech produced by 80 speakers of Spanish. Although the most common phonetic variant of /r/ contained two lingual constrictions, we find substantial inter-speaker variation in our data, ranging from zero to five lingual contacts. The results demonstrate that the variation in Spanish results from a systematic interaction of factors, deriving from well-documented processes of consonantal lenition (e.g., weakening in unstressed syllables) in addition to processes inherent to the trill's articulation (e.g., high-vowel antagonism). Importantly, speaker sex displayed the strongest effect among all the predictors, which leads us to consider the role of sociolinguistic factors, in addition to possible biomechanical differences, on /r/ production. We contextualize the findings within a literature that theorizes rhotic consonants as a single class of sounds despite remarkable patterns of cross-language and speaker-specific variation.

The relationship between speaking rate and burst amplitude was investigated in plosives with differing oro-laryngeal timing: long-lag voice-onset time (VOT) (North American English) and short-lag VOT (Indian Tamil). Burst amplitude (reflecting both intraoral pressure and flow geometry of the oral channel) was hypothesized to decrease in pre-vocalic plosive syllables with the increase in speaking rate, which imposes temporal constraints on both intraoral pressure buildup behind the oral occlusion and respiratory air flow. The results showed that decreased vowel duration (which is associated with increased speaking rate) led to decreased burst amplitude in both short- and long-lag plosives. Aggregate models of bilabial and velar plosives (found in both languages) suggested lower burst amplitudes in short-lag stops. Place-of-articulation effects in both languages were consistent with models of stop consonant acoustics, and place interactions with vowel duration were most apparent with long-lag English stops. The results are discussed in terms of speaking rate and language-internal forces, contributing to burst amplitude variation and their implications for speech perception and potential to affect lenition phenomena.

The voicing effect is among the most studied and robust of phonetic phenomena. Yet there remains a lack of consensus on why vowels preceding voiced obstruents should be longer than vowels preceding voiceless obstruents. In this paper we provide an analysis of the voicing effect in a corpus of natural speech, and using production data from a metronome-timed word repetition study. From this evidence, as well as the existing literature, we conclude that vowel duration differences follow from consonant duration differences. The characteristic voicing effect in English is largely limited to words of especially long duration, and preceding vowel duration does not reliably cue obstruent voicing under the following circumstances: when obstruent voicing or duration cues conflict; for lax or unstressed vowels; and for most conversational speech. We show that this behavior can be modeled using a competing-constraints framework, where all segments resist expanding or compressing past a preferred duration. Inherent segment elasticity determines the degree of resistance, but segment duration is ultimately determined by the interaction of these segmental constraints with constraints on the distribution of the lengthening force within the syllable, and how closely target durations are matched. This account of the voicing effect has a number of implications for phonological theory, especially the central role that the concept of prominence plays in the analysis of underlying features.

Empirical evidence and theoretical models suggest that phonetic category perception involves two stages of auditory and phonetic processing. However, few studies examined the time course of these two processing stages. With brief stop consonant segments as context stimuli, this study examined the temporal dynamics of stop consonant perception by varying the inter-stimulus interval between context and target stimuli. The results suggest that phonetic category activation of stop consonants may appear before 100 ms of processing time. Furthermore, the activation of phonetic categories resulted in contrast context effects on identifying the target stop continuum; the auditory processing of stop consonants resulted in a different context effect from those caused by phonetic category activation. The findings provide further evidence for the two-stage model of speech perception and reveal the time course of auditory and phonetic processing.

Previous studies have suggested the effect of linguistic information on voice perception (e.g., the language-familiarity effect [LFE]). However, it remains unclear which type of specific information in speech contributes to voice perception, including acoustic, phonological, lexical, and semantic information. It is also underexamined whether the roles of these different types of information are modulated by the experimental paradigm (speaker discrimination vs. speaker identification). In this study, we conducted two experiments to investigate these issues regarding LFEs. Experiment 1 examined the roles of acoustic and phonological information in speaker discrimination and identification with forward and time-reversed Mandarin and Indonesian sentences. Experiment 2 further identified the roles of phonological, lexical, and semantic information with forward, word-scrambled, and reconstructed (consisting of pseudo-Mandarin words) Mandarin and forward Indonesian sentences. For Mandarin-only participants, in Experiment 1, speaker discrimination was more accurate for forward than reversed sentences, but there was no LFE in either sentence. Speaker identification was also more accurate for forward than reversed sentences, whereas there was an LFE for forward sentences. In Experiment 2, speaker discrimination was better for word-scrambled than reconstructed Mandarin sentences. Speaker identification was more accurate for forward and word-scrambled Mandarin sentences but less accurate for Mandarin reconstructed and forward Indonesian sentences. In general, the pattern of the results for Indonesian learners was the same as that for Mandarin-only speakers. These results suggest that different kinds of information support speaker discrimination and identification in native and unfamiliar languages. The LFE in speaker identification depends on both phonological and lexical information.

Lexical tones are known to be a challenging aspect of speech to acquire in a second language, but several factors are known to affect tone learning facility, such as L1 tonal status (whether a learner's L1 is tonal or not), tone type (the shape of the tones to be acquired), and individual extralinguistic factors (such as musicianship, pitch aptitude, and working memory). Crucially, most of our knowledge of the effect of these factors is based on evidence from perception. The production side of tone learning and the origins of individual variability in learning facility remain relatively understudied. To this end, this study investigated non-native tone production-both in terms of phonetic accuracy in a pseudoword imitation task and in terms of phono-lexical accuracy in a picture-naming task-by English-L1 and Mandarin-L1 speakers. Results show that L1 tonal status and tone type dynamically affected both imitation and picture-naming accuracy, as there were specific accuracy patterns for the English and Mandarin groups. Production accuracy was further facilitated by individual musical experience, working memory, and pitch aptitude. This study's findings add to the currently limited literature on how both language-specific and individual extralinguistic factors modulate non-native tone processing in the speaking modality.

English listeners often struggle to perceive tones, but some are easier than others. This study examined these phenomena grounded in the feature weighing perspective (FWP) and the Perceptual Assimilation Model for Suprasegmentals (PAM-S). Forty-seven English and Cantonese listeners completed 4,212 trials of Cantonese tone discrimination and sequence recall tasks. The English listeners showed asymmetrical perceptual patterns of discrimination but not sequence recall. Specifically, these English listeners discriminated T1-T5, T3-T5, and T4-T5 more accurately than T1-T4, T3-T4, and T1-T3. However, they recalled the contour tone and level tone sequences with similar accuracies. Results of the discrimination task aligned with the predictions of PAM-S but not FWP. However, results of the sequence recall task did not support PAM-S. Together, these results suggest that PAM-S only applies to simple discrimination, not abstract phonological processing with a high memory load.

Individual talkers vary in their relative use of different cues to signal phonological contrast. Previous work provides limited and conflicting data on whether such variation is modulated by cue trading or individual differences in speech style. This paper examines differential cue weighting patterns in Mandarin sibilants as a test case for these hypotheses. Standardized Mandarin exhibits a three-way place contrast between retroflex, alveopalatal, and alveolar sibilants with individual differences in relative weighting of spectral center of gravity (COG) and the second formant of the following vowel (F2). In results from a speech production task, cue weights of COG and F2 are inversely correlated across speakers, demonstrating a trade-off relationship in cue use. These findings are consistent with a cue trading account of individual differences in contrast signaling.

In many English varieties, /l/ is produced differently in onsets and codas. Compared with "light" syllable-initial realizations, "dark" syllable-final variants involve reduced tongue tip-alveolar ridge contact and a raised/retracted tongue dorsum. We investigate whether native French and Spanish speakers whose L1 lacks such positionally conditioned variation can acquire English-/l/ allophony, testing the hypotheses that (1) the allophonic pattern will be acquired by both groups but (2) learners will differ from native speakers in their phonetic implementation, particularly in codas; and (3) French-speaking learners will outperform their Spanish-speaking counterparts. The production of syllable-initial and -final /l/ (singletons and clusters) in words read in isolation and a carrier sentence by 4 French- and 3 Spanish-speaking learners as well as three native English speakers was analyzed via electropalatography and acoustic analysis. While some learners produced distinct onset and coda variants and all learners had moved away to some extent from their L1 production, they differed from the native speakers in certain ways. Moreover, between- and within-group variability was observed including greater target-like anterior and posterior contact reduction in codas in the L1 French versus L1 Spanish group and generally higher F2 values in both learner groups compared with their native speaker peers. A comparison of the learners' L1 and L2 production revealed L1-based patterns of positional reduction of the tongue tip and dorsum gestures. We conclude by addressing the contributions of EPG to our understanding of L2 speech and highlight avenues for future research including the study of both linguistic and speaker variables.