Phonemic Contrasts Research Articles

Perception of Japanese mora nasal /N/ and mora obstruent /Q/ by native Japanese and English speakers

Japanese mora nasal /N/ and more obstruent /Q/ have no definite point of articulation. For instance, /N/ becomes [m] when a bilabial consonant follows and [n] when an alveolar consonant follows. /Q/ is also realized as [p], [t], or [k], depending on the point of articulation of the following consonant. Four native speakers of Japanese produced /N/ and /Q/ in /CVNCV/ and /CVQCV/ contexts, where the consonant after /N/ and /Q/ is always a stop. Their utterances were recorded and digitized. The word final /CV/ was edited out, and the stimuli with the structure of /CVN/ and /CVQ/ were created. Twelve native speakers of Japanese and American English were recruited as listeners in Shiga, Japan and Auburn, AL, respectively. The American listeners were told to identify the word final consonant in a multiple-choice format. The Japanese listeners were told that they were to tell whether /Q/ and /N/ were realized as [m], [n], [■], and [p], [t], [k], respectively. The American listeners outperformed the Japanese listeners despite the fact that they had had no prior exposure to Japanese. This is probably because a stop does not occur or no phonemic contrast is allowed in a postvocalic position in Japanese.

Effects of dialect variation on speeded word classification

Dialect variation has been found to significantly affect speech intelligibility in noise. The current experiment was designed to examine the effects of dialect variation on the processing of a single phonemic contrast. Participants were presented with tokens of the words ‘‘bad’’ and ‘‘bed’’ produced by talkers from Chicago and Indianapolis. The vowels in the Chicago tokens were shifted according to the Northern Cities shift (raised and fronted ‘‘bad,’’ lowered and backed ‘‘bed’’). The Indianapolis tokens were unshifted. The participants were asked to classify each token as ‘‘bad’’ or ‘‘bed’’ as quickly as possible in three conditions: Chicago tokens only, Indianapolis tokens only, or mixed Chicago and Indianapolis tokens. While overall accuracy was high in all three conditions, participants were slower in the Chicago-only and mixed conditions than in the Indianapolis-only condition. In addition, participants responded more slowly to the Indianapolis tokens in the mixed condition than in the Indianapolis-only condition, but response times to the Chicago tokens did not differ across the two conditions. These results suggest that acoustic-phonetic dialect differences interfere with lexical processing and that global effects of dialect variation on speech intelligibility may reflect confusions between specific pairs of phonemes as a result of subphonemic vowel shifts.

Phonemic contrast enhancement in clear speech production: The case of Korean stop production

This study explores the code enhancement aspect of clear speech production. Younger (n=11, 20–29 years old) and older (n=11, 40–60 years old) speakers of Korean produced the three series of Korean stops (aspirated, lenis, fortis) in three different speaking styles: conversational, citation-form, and clear speech. The production of Korean stops was analyzed for three acoustic properties differentiating the Korean stops, voice onset time (VOT), amplitude difference between the first and the second harmonics (H1-H2), and fundamental frequency (F0). For both of the younger and older groups, the VOT difference between the aspirated and lenis stops was enhanced in clear speech, in addition to enhanced difference between the aspirated/lenis and fortis stops for H1-H2. The two groups differed in that only the younger speakers showed a substantial increase in F0 for the production of the aspirated stops in clear speech. Also, there was a substantial degree of interspeaker variability in the size and direction of the acoustic adjustment in clear speech. The results of this study support Silva’s [Phonology 23, 287–308 (2006)] proposal that younger and older Korean speakers may use different strategies in order to maintain a distinction between the three types of Korean stops.

Stress sensitivity and reading performance in Spanish: A study with children

This paper investigates the relationship between ability to detect changes in prosody and reading performance in Spanish. Participants were children aged 7–8 years. Their tasks consisted of reading words, reading non‐words, stressing non‐words and reproducing sequences of two, three or four non‐words by pressing the corresponding keys on the computer keyboard. Non‐word sequences were constructed with minimal non‐word pairs differing in a single phoneme (/kúpi/ ‐ /kúti/) or in the stress pattern (/mípa/ ‐ /mipá/). Results showed that performance on phoneme contrast sequences (e.g. /kúpi/ ‐ /kúti/) predicted word reading. In contrast, performance on stress contrast sequences (e.g. /mípa/ ‐ /mipá/) predicted non‐word reading, but only when two‐non‐word sequences were analysed. This suggests that stress sensitivity may be one of the factors related to reading fluency as most errors at reading non‐words consisted of false starts and pauses between syllables. Results also showed that stress sensitivity (scored in two non‐word sequences) predicted stress assignment, and that knowledge of stress rules predicted both word and non‐word reading. This suggests that stress sensitivity may help in learning stress rules, and that knowledge of stress rules is relevant for reading.

Auditory processing disorder in children with reading disabilities: effect of audiovisual training

Reading disability is associated with phonological problems which might originate in auditory processing disorders. The aim of the present study was 2-fold: first, the perceptual skills of average-reading children and children with dyslexia were compared in a categorical perception task assessing the processing of a phonemic contrast based on voice onset time (VOT). The medial olivocochlear (MOC) system, an inhibitory pathway functioning under central control, was also explored. Secondly, we investigated whether audiovisual training focusing on voicing contrast could modify VOT sensitivity and, in parallel, induce MOC system plasticity. The results showed an altered voicing sensitivity in some children with dyslexia, and that the most severely impaired children presented the most severe reading difficulties. These deficits in VOT perception were sometimes accompanied by MOC function abnormalities, in particular a reduction in or even absence of the asymmetry in favour of the right ear found in average-reading children. Audiovisual training significantly improved reading and shifted the categorical perception curve of certain children with dyslexia towards the average-reading children's pattern of voicing sensitivity. Likewise, in certain children MOC functioning showed increased asymmetry in favour of the right ear following audiovisual training. The training-related improvements in reading score were greatest in children presenting the greatest changes in MOC lateralization. Taken together, these results confirm the notion that some auditory system processing mechanisms are impaired in children with dyslexia and that audiovisual training can diminish these deficits.

On the Proto-Indo-European Obstruent System

1. The problem The traditional reconstruction of Proto-Indo-European has a threeway phonemic contrast in the stops *p : *b : *bh, *t : *d : *dh, *k : *g : *gV This distribution is not found in the majority of the well-attested daughter families. Anatolian and Tokharian, which may be called 'group A', have no phonemic voiced stops,2 while Celtic, Baltic, Slavic, Albanian, and Iranian, which may be referred to as 'group C' have only a two-way distinction between voiced and unvoiced stops, so there is only one voiced series, *b, *d, *g. The three-way system has been reconstructed on the basis of Germanic, Greek, Italic, Armenian, and Indie, which may be called 'group B'.3 However, because even in group B only a two-way opposition is reconstructible for the labials in initial position (PIE *p : *bh), as demonstrated by Grassmann (1863/1967: 120-121), Proto-Indo-European has usually been reconstructed with a missing initial *b (Szemerenyi 1996: 145). Unfortunately, a system with a missing voiced labial stop *b is unprecedented typologically, unlike a missing unvoiced stop *p, which is a frequent occurrence cross-linguistically. Moreover, the traditional three-way phoneme system unvoiced unaspirate : voiced unaspirate : voiced aspirate is not merely unnatural, it seems to be unattested in any known language, as noted by Jakobson in 1958 (Miller 1977).

Neural Attunement Processes in Infants during the Acquisition of a Language-Specific Phonemic Contrast

To elucidate the developmental neural attunement process in the language-specific phonemic repertoire, cerebral hemodynamic responses to a Japanese durational vowel contrast were measured in Japanese infants using near-infrared spectroscopy. Because only relative durational information distinguishes this particular vowel contrast, both first and second language learners have difficulties in acquiring this phonemically crucial durational difference. Previous cross-linguistic studies conducted on adults showed that phoneme-specific, left-dominant neural responses were observed only for native Japanese listeners. Using the same stimuli, we show that a larger response to the across-category changes than to the within-category changes occurred transiently in the 6- to 7-month-old group before stabilizing in the groups older than 12 months. However, the left dominance of the phoneme-specific response in the auditory area was observed only in the groups of 13 months and above. Thus, the durational phonemic contrast is most likely processed first by a generic auditory circuit at 6-7 months as a result of early auditory experience. The neural processing of the contrast is then switched over to a more linguistic circuit after 12 months, this time with a left dominance similar to native adult listeners.

The role of phonemic contrast in the formation of Sino-Japanese

When a language adapts words from another language, the adapting language (L1) naturally tries to retain the phonemic contrasts of the source language (L2). However, if the L2 has a greater degree of contrast than the L1 then either the extra degree(s) of contrast will be lost, or the L1 must introduce markedness into its phonological system. The objective of this article is twofold First, I argue that the introduction of markedness into the L1’s phonology when adapting words from another language correlates with the social relationship between the languages. I demonstrate this by examining the retention of phonemic contrast in the various stages of the adaptation of Chinese words into Japanese Second, I argue for a phonological constraint that enforces the retention of L2’s phonemic contrast, DISTINCT. An Optimality Theoretic analysis of the adaptation of Sino-Japanese produces the expected results for all of stages of adaptation except one—the stage when contact between the two languages is at its peak. For this stage, the analysis requires the addition of the DISTINCT constraint

The effect of language experience on the perception of coronal stop bursts

The difficulty of perceiving a phonetic contrast not present in one’s native language is well known. However, there is also research showing that discrimination of non‐native sounds that are sufficiently far from a listener’s language is possible even in adulthood, as in the case of English speakers discriminating Zulu clicks [Best et al. (1988)]. This raises the question of whether listeners’ ability to discriminate contrasts can hinge on whether listeners are perceiving sounds as speech or non‐speech. To test whether language experience affects all auditory perception or only linguistic perception, the current study investigates the ability of Bengali and English speakers to identify isolated Bengali dental and post‐alveolar stop bursts in an ABX task, where the bursts are first described as sounds in nature (i.e., non‐linguistic context) and later as sounds in language (i.e., linguistic context). It is predicted that, due to the phonemic contrast of dental and post‐alveolar stops in their language, Bengali speakers will perform better than English speakers in the linguistic context, and that English speakers will perform better in the non‐linguistic context than in the linguistic context.

Acoustic evidence for the lenis/fortis contrast in California Northern Paiute

California Northern Paiute (CNP) is spoken in the communities on the eastern slopes of the Sierra Nevada Mountains in northern California. CNP is the southernmost dialect of Northern Paiute, a language belonging to the Western Numic branch of Uto-Aztecan. CNP is a severely endangered language spoken by fewer than ten fluent speakers. CNP has a phonemic contrast that is distinct from that of any other Numic language. CNP has three series of stops: lenis, fortis, and voiced fortis. Previous descriptions of CNP have used only impressionistic judgments to categorize the phoneme series. This paper presents the first acoustic evidence for the lenis/fortis contrast in CNP. Field recordings from five native speakers of CNP were analyzed in this investigation. The lenis/fortis contrast was examined by measuring the closure duration using cues from the waveform and spectrogram in a digital signal processing program. Results of duration measurements support the impressionistic evidence and suggest a voiced and voiceless fortis series in addition to a single lenis series in the phonemic inventory of CNP. This research has implications for the acquisition of categories by second language learners who are first language speakers of a language that does not have such a contrast.

The effect of distributional information on children’s use of phonemic contrasts

Several recent experiments indicate that, when learning words, children are not as sensitive to phonemic differences (e.g., /d/ vs. /t/) as they are in discrimination tasks [Pater, J., Stager, C. L., & Werker, J. F. (2004). The perceptual acquisition of phonological contrasts. Language, 80, 384–402; Stager, C. L., & Werker, J. F. (1997). Infants listen for more phonetic detail in speech perception than in word-learning tasks. Nature, 388, 381–382]. In particular, 14-month-olds who can hear the difference between similar words such as “daw” and “taw” treat these labels as interchangeable when they refer to newly learned objects. We hypothesize that experience with the distribution of phonemes in their native language helps children use these phonemic distinctions in a word-learning task. Children receive distributional information when they experience different phonemes in different words. To test this hypothesis, we exposed children to two kinds of words: words in which phonemes occurred in very similar contexts, and words in which phonemes occurred in dissimilar contexts. Children who experienced phonemes in dissimilar contexts were more successful in using the contrast between the phonemes in a word-learning task.

Visual Phonemic Ambiguity and Speechreading

To study the role of visual perception of phonemes in visual perception of sentences and words among normal-hearing individuals. Twenty-four normal-hearing adults identified consonants, words, and sentences, spoken by either a human or a synthetic talker. The synthetic talker was programmed with identical parameters within phoneme groups, hypothetically resulting in simplified articulation. Proportions of correctly identified phonemes per participant, condition, and task, as well as sensitivity to single consonants and clusters of consonants, were measured. Groups of mutually exclusive consonants were used for sensitivity analyses and hierarchical cluster analyses. Consonant identification performance did not differ as a function of talker, nor did average sensitivity to single consonants. The bilabial and labiodental clusters were most readily identified and cohesive for both talkers. Word and sentence identification was better for the human talker than the synthetic talker. The participants were more sensitive to the clusters of the least visible consonants with the human talker than with the synthetic talker. It is suggested that ability to distinguish between clusters of the least visually distinct phonemes is important in speechreading. Specifically, it reduces the number of candidates, and thereby facilitates lexical identification.

Sensitivity to Word-Final Phonotactics in 9- to 16-Month-Old Infants.

Previous research has shown that infants begin to display sensitivities to language-specific phonotactics and probabilistic phonotactics at around 9 months of age. However, certain phonotactic patterns have not yet been examined, such as contrast neutralization, in which phonemic contrasts are neutralized typically in syllable- or word-final position. Thus, the acquisition of contrast neutralization is dependent on infants' ability to perceive certain contrasts in final position. The studies reported here test infants' sensitivity to voicing neutralization in word-final position and infants' discrimination of voicing and place of articulation (POA) contrasts in word-initial and word-final position. Nine and 11-month-old Dutch-learning infants showed no preference for legal versus illegal voicing phonotactics that were contrasted in word-final position. Furthermore, 10-month-old infants showed no discrimination of voicing or POA contrasts in word-final position, whereas they did show sensitivity to the same contrasts in word-initial position. By 16 months, infants were able to discriminate POA contrasts in word-final position, although showing no discrimination of the word-final voicing contrast. These findings have broad implications for models of how learners acquire the phonological structures of their language, for the types of phonotactic structures to which infants are presumed to be sensitive, and for the relative sensitivity to phonemic distinctions by syllable and word position during acquisition.

Early learners’ discrimination of second-language vowels

It is uncertain from previous research to what extent the perceptual system retains plasticity after attunement to the native language (L1) sound system. This study evaluated second-language (L2) vowel discrimination by individuals who began learning the L2 as children ("early learners"). Experiment 1 identified procedures that lowered discrimination scores for foreign vowel contrasts in an AXB test (with three physically different stimuli per trial, where "X" was drawn from the same vowel category as "A" or "B"). Experiment 2 examined the AXB discrimination of English vowels by native Spanish early learners and monolingual speakers of Spanish and English (20 per group) at interstimulus intervals (ISIs) of 1000 and 0 ms. The Spanish monolinguals obtained near-chance scores for three difficult vowel contrasts, presumably because they did not perceive the vowels as distinct phonemes and because the experimental design hindered low-level encoding strategies. Like the English monolinguals, the early learners obtained high scores, indicating they had shown considerable perceptual learning. However, statistically significant differences between early learners and English monolinguals for two of three difficult contrasts at the 0-ms ISI suggested that their underlying perceptual systems were not identical. Implications for claims regarding perceptual plasticity following L1 attunement are discussed.

The use of visual cues in the perception of non-native consonant contrasts

This study assessed the extent to which second-language learners are sensitive to phonetic information contained in visual cues when identifying a non-native phonemic contrast. In experiment 1, Spanish and Japanese learners of English were tested on their perception of a labial/ labiodental consonant contrast in audio (A), visual (V), and audio-visual (AV) modalities. Spanish students showed better performance overall, and much greater sensitivity to visual cues than Japanese students. Both learner groups achieved higher scores in the AV than in the A test condition, thus showing evidence of audio-visual benefit. Experiment 2 examined the perception of the less visually-salient /1/-/r/ contrast in Japanese and Korean learners of English. Korean learners obtained much higher scores in auditory and audio-visual conditions than in the visual condition, while Japanese learners generally performed poorly in both modalities. Neither group showed evidence of audio-visual benefit. These results show the impact of the language background of the learner and visual salience of the contrast on the use of visual cues for a non-native contrast. Significant correlations between scores in the auditory and visual conditions suggest that increasing auditory proficiency in identifying a non-native contrast is linked with an increasing proficiency in using visual cues to the contrast.

Remarks on the speech of Arabic-speaking children with cleft palate: three case studies

Speech samples were obtained from three Arabic-speaking children with cleft palate, and two questions were asked. First, are the characteristics of their speech like those reported for cleft palate speakers of other languages? This is interesting because cleft speech data for Arabic are so far unreported. Many characteristics seem similar, but implosive airstream, oral stop devoicing, and labiodental stopping also occurred. Second, do pharyngeal and glottal compensatory articulations, frequently reported for cleft speech, occur in Arabic? Since Arabic has phonemic , we might expect they do not, to avoid phonetic neutralisation of phonemic contrast. In the samples, compensatory pharyngeal and glottal articulations were produced. The resultant neutralisations, and the neutralisation from the children's uvular compensatory articulations, indicate that the children's productions were insensitive to the phonemics of the language. This is consistent with the conclusion elsewhere that the characteristics of clef...

Hearing lips in a second language: visual articulatory information enables the perception of second language sounds

We investigated the effects of visual speech information (articulatory gestures) on the perception of second language (L2) sounds. Previous studies have demonstrated that listeners often fail to hear the difference between certain non-native phonemic contrasts, such as in the case of Spanish native speakers regarding the Catalan sounds /epsilon/ and /e/. Here, we tested whether adding visual information about the articulatory gestures (i.e., lip movements) could enhance this perceptual ability. We found that, for auditory-only presentations, Spanish-dominant bilinguals failed to show sensitivity to the /epsilon/-/e/ contrast, whereas Catalan-dominant bilinguals did. Yet, when the same speech events were presented audiovisually, Spanish-dominants (as well as Catalan-dominants) were sensitive to the phonemic contrast. Finally, when the stimuli were presented only visually (in the absence of sound), none of the two groups presented clear signs of discrimination. Our results suggest that visual speech gestures enhance second language perception at the level of phonological processing especially by way of multisensory integration.

Lexical confusability and nasal coarticulation in French

Previous research has revealed a relationship between lexical confusability and degree of coarticulation [Brown (2001); Scarborough (2004)]. In particular, English speakers produce confusable, or ‘‘hard’’ words with more nasal and vowel-to-vowel coarticulation than less confusable, ‘‘easy’’ ones. Thus, it has been suggested that speakers produce additional coarticulation in order to increase the intelligibility of ‘‘hard’’ words. Here, the relation between nasal coarticulation and lexical confusability is investigated for French, a language in which vowel nasality is phonemically contrastive (at least for a subset of vowels) and might constrain such a lexical effect. Acoustic measures of nasality show that ‘‘hard’’ words (those with low usage frequencies and many frequent, phonologically similar neighbors) exhibit more nasal coarticulation than ‘‘easy’’ ones (those with high frequencies and few, low-frequency neighbors) in French as well. Interestingly, however, the effect emerges only for words containing vowels that can exhibit phonemic oral-nasal contrasts (oral vowels with nasal counterparts). Thus, where the use of nasality in phonological contrast is constrained, coarticulatory nasality is constrained, too. But the existence of phonological contrast does not itself constrain the lexical confusability effect: increased coarticulatory nasality contributes to lexically motivated phonetic enhancement in French, while even more nasality provides the basis for phonemic contrast.

Orthographic vs. morphological incomplete neutralization effects

This study, following up on work on Dutch by Warner, Jongman, Sereno, and Kemps (2004. Journal of Phonetics, 32, 251–276), investigates the influence of orthographic distinctions and underlying morphological distinctions on the small sub-phonemic durational differences that have been called incomplete neutralization. One part of the previous work indicated that an orthographic geminate/singleton distinction could cause speakers to produce an incomplete neutralization effect. However, one interpretation of the materials in that experiment is that they contain an underlying difference in the phoneme string at the level of concatenation of morphemes, rather than just an orthographic difference. Thus, the previous effect might simply be another example of incomplete neutralization of a phonemic distinction. The current experiment, also on Dutch, uses word pairs which have the same underlying morphological contrast, but do not differ in orthography. These new materials show no incomplete neutralization, and thus support the hypothesis that orthography, but not underlying morphological differences, can cause incomplete neutralization effects.

Effect of audiovisual perceptual training on the perception and production of consonants by Japanese learners of English

This study investigates whether L2 learners can be trained to make better use of phonetic information from visual cues in their perception of a novel phonemic contrast. It also evaluates the impact of audiovisual perceptual training on the learners’ pronunciation of a novel contrast. The use of visual cues for speech perception was evaluated for two English phonemic contrasts: the /v/–/b/–/p/ labial/labiodental contrast and /l/–/r/ contrast. In the first study, 39 Japanese learners of English were tested on their perception of the /v/–/b/–/p/ distinction in audio, visual and audiovisual modalities, and then undertook ten sessions of either auditory (‘A training’) or audiovisual (‘AV training’) perceptual training before being tested again. AV training was more effective than A training in improving the perception of the labial/labiodental contrast. In a second study, 62 Japanese learners of English were tested on their perception of the /l/–/r/ contrast in audio, visual and audiovisual modalities, and then undertook ten sessions of perceptual training with either auditory stimuli (‘A training’), natural audiovisual stimuli (‘AV Natural training’) or audiovisual stimuli with a synthetic face synchronized to natural speech (‘AV Synthetic training’). Perception of the /l/–/r/ contrast improved in all groups but learners trained audiovisually did not improve more than those trained auditorily. Auditory perception improved most for ‘A training’ learners and performance in the lipreading alone condition improved most for ‘natural AV training’ learners. The learners’ pronunciation of /l/–/r/ improved significantly following perceptual training, and a greater improvement was obtained for the ‘AV Natural training’ group. This study shows that sensitivity to visual cues for non-native phonemic contrasts can be enhanced via audiovisual perceptual training. AV training is more effective than A training when the visual cues to the phonemic contrast are sufficiently salient. Seeing the facial gestures of the talker also leads to a greater improvement in pronunciation, even for contrasts with relatively low visual salience.