The role of perception in the sound change of velar palatalization

Variation learning in phonology and morphosyntax

While variation occurs in both phonology and morphosyntax, phonological variation also includes phonetic variation motivated by articulatory or perceptual factors. While learning in both domains is subject to cognitive biases, phonological learning may also be biased by physical factors, which may enhance learnability of phonetically motivated alternations. This study aims to identify whether learning differs when children are exposed to phonological or morphosyntactic patterns with equal complexity. Cantonese-speaking children learned an artificial language involving rounding harmony, where unround [e] or round [o] harmonizes with the following noun, or gender agreement, with feminine and masculine allomorphs lo ~ le. Patterns applied variably in 67% of training items, or categorically. Children were tested on generalization to novel stems. In the categorical learning conditions, participants showed comparable rates of harmony/agreement. In the variable phonological learning conditions, application of harmony exceeded the rate of exposure in training, suggesting the influence of a bias toward phonetically grounded rounding harmony. In the variable morphosyntactic condition, participants applied agreement below the rate of exposure. This finding points to a qualitative difference between learning in the two domains, with phonological (but not morphosyntactic) learning influenced by substantive grounding.

Relationships of perception of health risks by use of pesticides: a man-environment look

The use of agricultural pesticides is increasingly linked to public health problems and negative impacts on the environment. Furthermore, Brazilian environmental agencies lack protective actions. Our objective in this study was to analyze the process that leads to the perception of the risks associated with the use of pesticides in the riverside agricultural communities of the San Francisco Valley in northeastern Brazil. We conducted a qualitative literature review, applying the Constructivist Grounded Theory to the analysis of published scientific articles. The elements of the perception process that we identified are (1) the environment; (2) conditioning factors; (3) perception of the human body; (4) memory; (5) socio-cognitive processing; (6) automatic response; (7) decision-making process; and (8) behavior. Each of these elements and their relationships indicate the location of the causes of inadequate perception, and thus guide potential solutions.

Visual Speech Perception Cues Constrain Patterns of Articulatory Variation and Sound Change

What are the factors that contribute to (or inhibit) diachronic sound change? While acoustically motivated sound changes are well-documented, research on the articulatory and audiovisual-perceptual aspects of sound change is limited. This paper investigates the interaction of articulatory variation and audiovisual speech perception in the Northern Cities Vowel Shift (NCVS), a pattern of sound change observed in the Great Lakes region of the United States. We focus specifically on the maintenance of the contrast between the vowels /ɑ/ and /ɔ/, both of which are fronted as a result of the NCVS. We present results from two experiments designed to test how the NCVS is produced and perceived. In the first experiment, we present data from an articulatory and acoustic analysis of the production of fronted /ɑ/ and /ɔ/. We find that some speakers distinguish /ɔ/ from /ɑ/ with a combination of both tongue position and lip rounding, while others do so using either tongue position or lip rounding alone. For speakers who distinguish /ɔ/ from /ɑ/ along only one articulatory dimension, /ɑ/ and /ɔ/ are acoustically more similar than for speakers who produce multiple articulatory distinctions. While all three groups of speakers maintain some degree of acoustic contrast between the vowels, the question is raised as to whether these articulatory strategies differ in their perceptibility. In the perception experiment, we test the hypothesis that visual speech cues play a role in maintaining contrast between the two sounds. The results of this experiment suggest that articulatory configurations in which /ɔ/ is produced with unround lips are perceptually weaker than those in which /ɔ/ is produced with rounding, even though these configurations result in acoustically similar output. We argue that these findings have implications for theories of sound change and variation in at least two respects: (1) visual cues can shape phonological systems through misperception-based sound change, and (2) phonological systems may be optimized not only for auditory but also for visual perceptibility.

Phonemes: Lexical access and beyond

Phonemes play a central role in traditional theories as units of speech perception and access codes to lexical representations. Phonemes have two essential properties: they are 'segment-sized' (the size of a consonant or vowel) and abstract (a single phoneme may be have different acoustic realisations). Nevertheless, there is a long history of challenging the phoneme hypothesis, with some theorists arguing for differently sized phonological units (e.g. features or syllables) and others rejecting abstract codes in favour of representations that encode detailed acoustic properties of the stimulus. The phoneme hypothesis is the minority view today. We defend the phoneme hypothesis in two complementary ways. First, we show that rejection of phonemes is based on a flawed interpretation of empirical findings. For example, it is commonly argued that the failure to find acoustic invariances for phonemes rules out phonemes. However, the lack of invariance is only a problem on the assumption that speech perception is a bottom-up process. If learned sublexical codes are modified by top-down constraints (which they are), then this argument loses all force. Second, we provide strong positive evidence for phonemes on the basis of linguistic data. Almost all findings that are taken (incorrectly) as evidence against phonemes are based on psycholinguistic studies of single words. However, phonemes were first introduced in linguistics, and the best evidence for phonemes comes from linguistic analyses of complex word forms and sentences. In short, the rejection of phonemes is based on a false analysis and a too-narrow consideration of the relevant data.

Voice onset time of alveolar stop /t/ and realization of unaspirated affricates associated with Mandarin-speaking children with repaired cleft palate

PURPOSE

To examine perceptually the realization of unaspirated affricates and voice onset time (VOT) features of /t/ in Mandarin-speaking children with repaired cleft palate, and to explore the difficulties associated with unaspirated affricate production from the perspective of the VOT of /t/.

METHOD

Twenty-three children with repaired cleft palate and 22 age-matched typical native Mandarin speakers were recruited. Speakers with cleft palate were allocated into two groups based on expert perceptual judgment of nasality: one group with perceived normal resonance (PNR) (n = 14, average age = 9.3 years), and another group with perceived hypernasal resonance (PHR) (n = 9, average age = 10.3 years).

INTERVENTION

Stimuli were collected through a series of picture naming tasks, targeting the production of initial consonants /t/ and three unaspirated Mandarin affricates /ts, tʂ, tɕ/. The productions of each affricate were evaluated by two experienced speech therapists. The VOT of /t/ was measured using PRAAT speech analysis software.

RESULT

The majority of unaspirated affricates were omitted and/or weakly realized by the group of PHR speakers, but not for the PNR group. A significantly smaller mean VOT value associated with /t/ was identified for the PHR group, as compared to the PNR group. A group difference for VOT value was not found between the PNR group and the typical control group.

CONCLUSION

The voicing features of /t/ and omitted/weak realization of unaspirated affricates identified in the PHR group indicated that the deviant production of unaspirated affricates in the cleft palate group could be associated with the voicing characteristics of the alveolar stop /t/, and this merits further investigation.

The perceptual assimilation of Korean obstruents by native Mandarin listeners

The current study reports the results of a perception experiment in which 20 naive native Mandarin listeners classified and rated the goodness of Korean stops /p, t, k, p(h), t(h), k(h), p*, t*, k*/, affricates /tɕ, tɕ*, tɕ(h)/, and fricatives /s(h), s*/ in terms of Mandarin segmental categories. It was found that listeners were sensitive to the voice onset time dimension of Korean stops and the presence of aspiration in Korean affricates, but Korean lenis and aspirated obstruents were generally assimilated to a single Mandarin category because the f0 cue differentiating them is not relevant to any Mandarin segmental contrast. The affricates were perceived as alveolopalatal and postalveolar more often than alveolar. The perception of fricatives was strongly influenced by vowel context, as the two fricatives were often perceived as different categories before /a/, but as the same category more often before /i/ and /u/. The results for the affricates and fricatives may be partly explained by Mandarin phonotactic constraints that prohibit alveolar and postalveolar consonants before /i/ and alveolopalatal consonants before /a/ or /u/.

Implications of an exemplar-theoretic model of phoneme genesis: a velar palatalization case study

Diachronic velar palatalization is taken as the case study for modeling the emergence of a new phoneme category. The spread of a palatalized variant through the lexicon is treated as a stochastic classification task for the listener/learner. The model combines two measures of similarity to determine classification within an exemplar-theoretic framework: acoustic distance and phonotactic expectation. There are three model outcomes: contrast, allophony, or contextual neutralization between the plain and palatalized velars. It is shown, through a series of simulations, that these can be predicted from the distribution of sounds within the pre-change lexicons, namely, the ratio of the /k-vowel/ sequences containing naturally palatalizing vowels (i, I, e), to those containing non-palatalizers. "Unnatural" phonotactic associations can arise in individual lexicons, but are sharply limited due to the large size of the lexicon and the local nature of the phoneme changes. "Anti-natural" distributions, which categorically violate the proposed implicational relationship between palatalization and frontness/height, are absent. This work provides an explicit and restrictive model of phoneme change. The results also serve as an existence proof for an outcome-blind mechanism of avoiding over-generation.

Language specificity in speech perception: perception of Mandarin tones by native and nonnative listeners

The results reported in this paper indicate that native speakers of Mandarin Chinese rate the perceptual similarities among the lexical tones of Mandarin differently than do native speakers of American English. Mandarin listeners were sensitive to tone contour while English listeners attended to pitch levels. Chinese listeners also rated tones that are neutralized by phonological tone sandhi rules in Mandarin as more similar to each other than did English speakers--indicating a role of phonology in determining perceptual salience. In two further experiments, we found that some of these differences were eliminated when the listening task focused listeners' attention on the auditory properties of the stimuli, but, interestingly, a degree of language specificity remained even in the most purely psychophysical listening tasks with speech stimuli.

Locus equations are an acoustic expression of articulator synergy

The study investigated the articulatory basis of locus equations, regression lines relating F2 at the start of a Consonant-Vowel (CV) transition to F2 at the middle of the vowel, with C fixed and V varying. Several studies have shown that consonants of different places of articulation have locus equation slopes that descend from labial to velar to alveolar, and intercept magnitudes that increase in the opposite order. Using formulas from the theory of bivariate regression that express regression slopes and intercepts in terms of standard deviations and averages of the variables, it is shown that the slope directly encodes a well-established measure of coarticulation resistance. It is also shown that intercepts are directly related to the degree to which the tongue body assists the formation of the constriction for the consonant. Moreover, it is shown that the linearity of locus equations and the linear relation between locus equation slopes and intercepts originates in linearity in articulation between the horizontal position of the tongue dorsum in the consonant and to that in the vowel. It is concluded that slopes and intercepts of acoustic locus equations are measures of articulator synergy.

Generalizing over Lexicons to Predict Consonant Mastery

When they first begin to talk, children show characteristic consonant errors, which are often described in terms that recall Neogrammarian sound change. For example, a Japanese child's production of the word kimono might be transcribed with an initial postalveolar affricate, as in typical velar-softening sound changes. Broad-stroke reviews of errors list striking commonalities across children acquiring different languages, whereas quantitative studies reveal enormous variability across children, some of which seems related to differences in consonant frequencies across different lexicons. This paper asks whether the appearance of commonalities across children acquiring different languages might be reconciled with the observed variability by referring to the ways in which sound change might affect frequencies in the lexicon. Correlational analyses were used to assess relationships between consonant accuracy in a database of recordings of toddlers acquiring Cantonese, English, Greek, or Japanese and two measures of consonant frequency: one specific to the lexicon being acquired, the other an average frequency calculated for the other three languages. Results showed generally positive trends, although the strength of the trends differed across measures and across languages. Many outliers in plots depicting the relationships suggested historical contingencies that have conspired to make for unexpected paths, much as in biological evolution."The history of life is not necessarily progressive; it is certainly not predictable. The earth's creatures have evolved through a series of contingent and fortuitous events." (Gould, 1989).