Bias for consonantal information over vocalic information in 30-month-olds: cross-linguistic evidence from French and English

Using a name-based categorization task, Nazzi found in 2005 that French-learning 20-month-olds can make use of one-feature consonantal contrasts between new labels but fail to do so with one-feature vocalic contrasts. This asymmetry was interpreted as developmental evidence for the proposal that consonants play a more important role than vowels at the lexical level. In the current study using the same task, we first show that by 30 months French-learning infants can make use of one-feature vocalic contrasts (e.g., /pize/–/pyze/). Second, we show that in a situation where infants must neglect either a consonantal one-feature change or a vocalic one-feature change (e.g., match a /pide/ with either a /tide/ or a /pyde/), both French- and English-learning 30-month-olds choose to neglect the vocalic change rather than the consonantal change. We argue that these results suggest that by 30 months of age, infants still give less weight to vocalic information than to consonantal information in a lexically related task even though they are able to process fine vocalic information.     

Segmentation of spoken words into syllables by English-speaking children as compared to adults

Given the importance of syllables in the development of reading, spelling, and phonological awareness, information is needed about how children syllabify spoken words. To what extent is syllabification affected by knowledge of spelling, to what extent by phonology, and which phonological factors are influential? In Experiment 1, six- and seven-year-old children did not show effects of spelling on oral syllabification, performing similarly on words such as habit and rabbit. Spelling influenced the syllabification of older children and adults, with the results suggesting that knowledge of spelling must be well entrenched before it begins to affect oral syllabification. Experiment 2 revealed influences of phonological factors on syllabification that were similar across age groups. Young children, like older children and adults, showed differences between words with "short" and "long" vowels (e.g., lemon vs. demon) and words with sonorant and obstruent intervocalic consonants (e.g., melon vs. wagon).     

Infant directed speech and the development of speech perception: Enhancing development or an unintended consequence?

Infant directed speech (IDS) is a speech register characterized by simpler sentences, a slower rate, and more variable prosody. Recent work has implicated it in more subtle aspects of language development. Kuhl et al. (1997) demonstrated that segmental cues for vowels are affected by IDS in a way that may enhance development: the average locations of the extreme “point” vowels (/a/, /i/ and /u/) are further apart in acoustic space. If infants learn speech categories, in part, from the statistical distributions of such cues, these changes may specifically enhance speech category learning. We revisited this by asking (1) if these findings extend to a new cue (Voice Onset Time, a cue for voicing); (2) whether they extend to the interior vowels which are much harder to learn and/or discriminate; and (3) whether these changes may be an unintended phonetic consequence of factors like speaking rate or prosodic changes associated with IDS. Eighteen caregivers were recorded reading a picture book including minimal pairs for voicing (e.g., beach/peach) and a variety of vowels to either an adult or their infant. Acoustic measurements suggested that VOT was different in IDS, but not in a way that necessarily supports better development, and that these changes are almost entirely due to slower rate of speech of IDS. Measurements of the vowel suggested that in addition to changes in the mean, there was also an increase in variance, and statistical modeling suggests that this may counteract the benefit of any expansion of the vowel space. As a whole this suggests that changes in segmental cues associated with IDS may be an unintended by-product of the slower rate of speech and different prosodic structure, and do not necessarily derive from a motivation to enhance development.     

Influence of consonantal context on the reading of vowels: evidence from children

When college students pronounce nonwords, their vowel pronunciations may be affected not only by the consonant that follows the vowel, the coda, but also by the preceding consonant, the onset. We presented the nonwords used by Treiman and colleagues in their 2003 study to a total of 94 first graders, third graders, fifth graders, and high school students to determine when these context influences emerge. According to some theories of reading development, early decoding is characterized by context-free links from graphemes to phonemes. However, we found that even children reading at the first-grade level (6-year-olds) were influenced to some extent by a vowel's context. The effect of context on vowel pronunciation increased in strength up to around the fifth-grade reading level (8- and 9-year-olds), and sensitivity to coda-to-vowel associations emerged no earlier than did sensitivity to onset-to-vowel associations. A connectionist model of reading reproduced this general pattern of increasing context effects as a function of training.     

Vowels, syllables, and letter names: differences between young children's spelling in English and Portuguese

Young Portuguese-speaking children have been reported to produce more vowel- and syllable-oriented spellings than have English speakers. To investigate the extent and source of such differences, we analyzed children's vocabulary and found that Portuguese words have more vowel letter names and a higher vowel-consonant ratio than do English words. In a spelling experiment, we found that Portuguese speakers used more vowels, but did not produce more syllabic spellings, than did English speakers. The differences that we observed are attributable to quantitative differences in the languages and their writing and letter name systems. They do not support the widespread idea that speakers of Romance languages pass through an additional, syllabic, stage of development.     

Neural correlates in the processing of phoneme-level complexity in vowel production

We investigated how articulatory complexity at the phoneme level is manifested neurobiologically in an overt production task. fMRI images were acquired from young Korean-speaking adults as they pronounced bisyllabic pseudowords in which we manipulated phonological complexity defined in terms of vowel duration and instability (viz., COMPLEX: /ti?i/ >> MID-COMPLEX: /tiye/ >> SIMPLE: /tii/). Increased activity in the left inferior frontal gyrus (Brodmann Areas (BA) 44 and 47), supplementary motor area and anterior insula was observed for the articulation of COMPLEX sequences relative to MID-COMPLEX; this was the case with the articulation of MID-COMPLEX relative to SIMPLE, except that the pars orbitalis (BA 47) was dominantly identified in the Broca’s area. The differentiation indicates that phonological complexity is reflected in the neural processing of distinct phonemic representations, both by recruiting brain regions associated with retrieval of phonological information from memory and via articulatory rehearsal for the production of COMPLEX vowels. In addition, the finding that increased complexity engages greater areas of the brain suggests that brain activation can be a neurobiological measure of articulo-phonological complexity, complementing, if not substituting for, biomechanical measurements of speech motor activity.     

Exploration of vocal tract properties during serial production of vowels by full term and preterm infants

This study examines the acoustic characteristics of individual vowels and those produced in sequences of three or more during vocal play by full term and preterm at age 6 months. Laboratory and home audiotape recordings of infant vowel sounds were made and digitized for acoustic analysis. Of interest was whether, during production of vowel sequences compared to those produced singly, infants explored the relation between tongue height and tongue advancement, as measured acoustically by the first formant (F1) and second formant (F2) frequencies, respectively. In both groups of infants, the region of F1-F2 space for individually produced vowels was significantly greater than for vowels produced in sequence. High correlation coefficients for F1 and F2 during exploration of vowels produced in sequence were apparent in full term, but not preterm infants. The data support the claim that vowels produced in sequence occupy a more limited region of the vocal tract than those produced singly, and that infants explore the characteristics of their vocalizations within sequences.     

The Role of Native-Language Phonology in the Auditory Word Identification and Visual Word Recognition of Russian–English Bilinguals

Does native language phonology influence visual word processing in a second language? This question was investigated in two experiments with two groups of Russian-English bilinguals, differing in their English experience, and a monolingual English control group. Experiment 1 tested visual word recognition following semantic categorization of words containing four phonological vowel contrasts (\({/{{\rm i}}/-/{{\rm u}}/, /{{\rm I}}/-/\wedge/, /{{\rm i}}/-/{{\rm I}}/, /{{\varepsilon}}/-/\ae/}\)). Experiment 2 assessed auditory identification accuracy of words containing these four contrasts. Both bilingual groups demonstrated reduced accuracy in auditory identification of two English vowel contrasts absent in their native phonology (\(/{{\rm i}}/-/{{\rm I}}/, /{\varepsilon}/-/\ae/\)). For late- bilinguals, auditory identification difficulty was accompanied by poor visual word recognition for one difficult contrast (/i/-/I/). Bilinguals’ visual word recognition moderately correlated with their auditory identification of difficult contrasts. These results indicate that native language phonology can play a role in visual processing of second language words. However, this effect may be considerably constrained by orthographic systems of specific languages.     

Cross‐Situational Learning of Minimal Word Pairs

Cross‐situational statistical learning of words involves tracking co‐occurrences of auditory words and objects across time to infer word‐referent mappings. Previous research has demonstrated that learners can infer referents across sets of very phonologically distinct words (e.g., WUG, DAX), but it remains unknown whether learners can encode fine phonological differences during cross‐situational statistical learning. This study examined learners’ cross‐situational statistical learning of minimal pairs that differed on one consonant segment (e.g., BON–TON), minimal pairs that differed on one vowel segment (e.g., DEET–DIT), and non‐minimal pairs that differed on two or three segments (e.g., BON–DEET). Learners performed above chance for all pairs, but performed worse on vowel minimal pairs than on consonant minimal pairs or non‐minimal pairs. These findings demonstrate that learners can encode fine phonetic detail while tracking word‐referent co‐occurrence probabilities, but they suggest that phonological encoding may be weaker for vowels than for consonants.