Journal of Phonetics最新文献

This study investigates how word categories, namely noun and verb, influence acoustic realizations (duration, F0, intensity) in Standard Mandarin Chinese, a language having phonemically distinctive tones and a simple morphological system. Noun-verb ambiguous words were selected and presented in the final positions of typical syntactic contexts in order to avoid the interference of prosodic boundary, syntactic complexity, contextual predictability, tonal environment, F0 range and syllable properties (consonant, vowel, tone, syllable length). Linear mixed models were fitted to duration, and generative additive mixed models were fitted to F0 and intensity. The results showed that phonetic differences between nouns and verbs were still evident in duration, F0 and intensity after lexical frequency, speech rate and some other related factors were taken into consideration in the models. The second syllables of nouns were longer than those of verbs, and both syllables of nouns were higher in F0 and greater in intensity than those of verbs. Since the prosodic boundary, frequency and other factors were controlled for, the phonetic differences between nouns and verbs might be attributed to their differences in information load and number of syllables. This study provided evidence that phonetic differences between nouns and verbs might be driven by the grammatical classes themselves and is not an epiphenomenon of other processes.

In some languages, breathy voice plays a pivotal role in tone split. After tone split, breathy voice can undergo further changes. Suzhou Wu Chinese used to have a voicing contrast in initial obstruents, which has transphonologized to a tone contrast and resulted in a two-way tone split, with breathy voice in the low register tones. This study investigates the change in breathy voice after the tone split in Suzhou Wu with apparent-time data from speakers from three age groups. Simultaneous audio and electroglottographic recordings were collected. Principal component analysis and linear discriminant analysis conducted on the acoustic measurements indicate that breathy voice is used less by younger speakers. Generalized Additive Mixed Models were conducted to reveal the changes in breathy voice during the time course of the vowel with regard to different low register tones. It is also found that T2 and T8 are undergoing a decrease in breathy voice with tone changes, but breathy voice is decreasing without tone change in T6. Younger female speakers are ahead of younger male speakers in the decrease in breathy voice. This paper provides a valuable investigation of the change in breathy voice after tone split and contributes to our understanding of the development of phonation types.

The study presented here examines how adult L2 listeners’ L1 phonotactics interferes with L2 vowel perception in different consonantal contexts. We examined Mandarin listeners’ perception of the English /ei/-/iː/ vowel contrast in three onset consonantal contexts, /p f w/, which represent different phonotactic scenarios with respect to the permissibility of Mandarin phonology. L1 Mandarin listeners (N = 42) completed a series of three tasks: a categorisation task, a vowel identification task, and an AXB discrimination task. The results show that English /ei/-/iː/ are perceived as highly contrastive in the /p/ context because both /pei/ and /piː/ constitute a licit sequence in Mandarin phonology. However, participants experience substantial /ei/-/iː/ category confusion in the /f/ and /w/ contexts, where Mandarin listeners repair perceptually by modifying the vowel quality in illicit (unattested) consonant–vowel sequences, i.e., */fiː/ → /fei/ and */wiː/ → /wei/. Further exploratory analyses indicate that L2 listeners’ vowel perception in unfamiliar phonotactic contexts is associated with their target language experience, typically indicated by their L2 vocabulary size. The findings thus suggest that the acquisition of novel phonotactic regularities is tied to increased experience with the L2 lexicon.

Phrase-final syllable duration and pauses are generally considered to be positively correlated: The stronger the boundary, the longer the duration of phrase-final syllables, and the more likely or longer a pause. Exploring a large sample of complex literary prose texts read aloud, we examined pause likelihood and duration, pre-boundary syllable duration, and the pitch excursion at prosodic boundaries. Comparing these features across six predicted levels of boundary strength (level 0: no break; 1: simple phrase break; 2: short comma phrase break; 3: long comma phrase break; 4: sentence boundary; 5: direct speech boundary), we find that they are not correlated in a simple monotonic fashion. Whereas pause duration monotonically increases with boundary strength, both pre-boundary syllable duration and the pitch excursion on the pre-boundary syllable are largest for level-2 breaks and decrease significantly through levels 3 to 5. Our analysis suggests that pre-boundary syllable duration is partly contingent on the tonal realization, which is subject to f0 declination as the utterance progresses. We also surmise that pre-boundary syllable duration reflects differences in planning complexity for the different prosodic and syntactic boundaries. Overall, this study shows that a simple monotonic correlation between pause duration and pre-boundary syllable duration is not valid.

Previous studies on the prosodic marking of information status argue that Italian tends to resist deaccentuation of given elements. In particular, Italian reportedly always accents post-focal given information within noun phrases (NPs), so that it is not possible to reliably reconstruct the information status of the items from the acoustic signal. However, descriptions have so far been concerned with categorical accent patterns, lacking crucial information about continuous phonetic parameters and their distribution in the utterance in ways that can contribute to prosodic marking. In this paper, we use a novel approach based on periodic-energy-related measures to explore how speakers of the Neapolitan variety of Italian modulate continuous prosodic parameters to differentiate information structure. We show that, contrary to previous findings, Italian speakers of the Neapolitan variety do mark information status prosodically within noun phrases. The discrepancy with previous work is explained by the fact that the prosodic marking of post-focal givenness is not achieved through the categorical presence or absence of a pitch accent on one specific syllable, but through the gradual modulation of phonetic parameters at various locations. Moreover, we find that these modulations occur early in the noun phrase. We also show that native speakers can make use of their knowledge of these modulations to reliably identify post-focal given elements in the absence of the pragmatic context, that is, directly from the acoustic signal.

Perceptual stability is obviously advantageous, but being able to adjust to the prevailing environment is also adaptive. Previous research has identified ways in which the categorization of speech sounds shifts as a function of recently heard speech. Dozens of studies have examined “lexically driven recalibration”, an adjustment to categorization after listeners hear a number of words with a particular speech sound designed to be perceptually ambiguous. Despite the large number of these studies, little is known about how long the adjustment endures. Using two different stimulus sets, we assess the recovery time after lexically driven recalibration. In addition, we examine whether the size of the recalibration effect diminishes during the identification test used to measure it, and whether the recalibration effect is stronger for one side of a tested contrast or the other. The effect did in fact decline during its measurement, and one side of the contrast (/s/) produced stronger shifts than others (/ʃ/ or /θ/) under the conditions typically examined in recalibration studies. Recalibration was quite robust after 24 hours for both stimulus sets, and still measurable after one week for one of them. This time course is strikingly different than the recovery times reported in previous studies for two other adjustment processes – selective adaptation and audiovisually driven recalibration. The vastly different time courses pose a major challenge for models that ascribe these phenomena to the same adjustment function. Thus, such models will need to be substantially modified, or alternative models will need to be developed.

Purpose

The acoustic signal attributes of whispered speech potentially carry sufficiently distinct information to define vowel spaces and to disambiguate consonant place and voicing, but what these attributes are and the underlying production mechanisms are not fully known. The purpose of this study was to define segmental cues to place and voicing of vowels and sibilant fricatives and to develop an articulatory interpretation of acoustic data.

Method

Seventeen speakers produced sustained sibilants and oral vowels, disyllabic words, sentences and read a phonetically balanced text. All the tasks were repeated in voiced and whispered speech, and the sound source and filter analysed using the following parameters: Fundamental frequency, spectral peak frequencies and levels, spectral slopes, sound pressure level and durations. Logistic linear mixed-effects models were developed to understand what acoustic signal attributes carry sufficiently distinct information to disambiguate /i, a/ and /s, ʃ/.

Results

Vowels were produced with significantly different spectral slope, sound pressure level, first and second formant frequencies in voiced and whispered speech. The low frequencies spectral slope of voiced sibilants was significantly different between whispered and voiced speech. The odds of choosing /a/ instead of /i/ were estimated to be lower for whispered speech when compared to voiced speech. Fricatives’ broad peak frequency was statistically significant when discriminating between /s/ and /ʃ/.

Conclusions

First formant frequency and relative duration of vowels are consistently used as height cues, and spectral slope and broad peak frequency are attributes associated with consonantal place of articulation. The relative duration of same-place voiceless fricatives was higher than voiced fricatives both in voiced and whispered speech. The evidence presented in this paper can be used to restore voiced speech signals, and to inform rehabilitation strategies that can safely explore the production mechanisms of whispering.

Vowel merger production is quantified with gradient acoustic measures, while phonemic perception methods are often coarser, complicating comparisons within mergers in progress. This study implements a perception experiment in two-dimensional formant space (F1 × F2), allowing unified plotting, quantification, and statistics with production data. Production and perception are compared within 20 speakers for a two-part prevelar merger in progress in Pacific Northwest English, where mid-front /ɛ, e/ approximate or merge before voiced velar /ɡ/ (leg–vague merger), and low-front prevelar /æɡ/ raises toward them (bag-raising). Distributions are visualized with kernel density plots and overlap quantified with Pillai scores and confusion matrices from linear discriminant analysis models. Results suggest that leg–vague merger is perceived as more complete than it is produced (in both the sample and community), while bag-raising is highly variable in production but rejected in perception. Relationships between production and perception varied by age, with raising and merger progressing across two generations in production but not perception, followed by younger adults perceiving leg–vague merger but not producing it and varying in (minimal) raising perception while varying in bag-raising in production. Thus, prevelar raising/merger may be progressing among some social groups but reversing in others.

Overlap of adjacent articulatory gestures leads to coarticulation. Understanding how hyperarticulated intelligibility-enhancing clear speech modifications affect coarticulation can inform theories of phonetic variation and speech intelligibility. However, prior research yielded mixed findings regarding the relationship between hyperarticulation and coarticulatory patterns. This study extends previous work by analyzing the degree of coarticulation across several different communicative conditions in the LUCID corpus (Baker & Hazan, 2010). Southern British English speakers completed an interactive spot-the-difference task with a partner with and without a communicative barrier (e.g., speech degraded by talker babble). They also read sentences without an interlocutor casually and clearly. Diphones in keywords produced in both tasks were analyzed using two whole-spectrum measures, with greater spectral distance and shorter coarticulatory overlap between the diphones indexing less coarticulation. Results revealed that speakers coarticulated less in response to both real (interactive task) and imaginary (sentence-reading) communicative challenges. Speakers furthermore varied the degree of coarticulatory resistance in different real communicative barriers. Diphones with greater consonant articulatory constraint were less sensitive to differences between the conditions, suggesting a limit to the hyperarticulation-induced phonetic variation. The findings agree with the models of targeted speaker adaptations assuming coarticulatory resistance in hyperarticulated clear speech (the H&H theory: Lindblom, 1990).