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Children who receive cochlear implants develop spoken language on a protracted timescale. The home environment facilitates speech-language development, yet it is relatively unknown how the environment differs between children with cochlear implants and typical hearing. We matched eighteen preschoolers with implants (31-65 months) to two groups of children with typical hearing: by chronological age and hearing age. Each child completed a long-form, naturalistic audio recording of their home environment (appx. 16 hours/child; >730 hours of observation) to measure adult speech input, child vocal productivity, and caregiver-child interaction. Results showed that children with cochlear implants and typical hearing were exposed to and engaged in similar amounts of spoken language with caregivers. However, the home environment did not reflect developmental stages as closely for children with implants, or predict their speech outcomes as strongly. Home-based speech-language interventions should focus on the unique input-outcome relationships for this group of children with hearing loss.

Purpose: Children with cochlear implants (CIs) are more likely to struggle with spoken language than their age-matched peers with normal hearing (NH), and new language processing literature suggests that these challenges may be linked to delays in spoken word recognition. The purpose of this study was to investigate whether children with CIs use language knowledge via semantic prediction to facilitate recognition of upcoming words and help compensate for uncertainties in the acoustic signal. Method: Five- to 10-year-old children with CIs heard sentences with an informative verb (draws) or a neutral verb (gets) preceding a target word (picture). The target referent was presented on a screen, along with a phonologically similar competitor (pickle). Children's eye gaze was recorded to quantify efficiency of access of the target word and suppression of phonological competition. Performance was compared to both an age-matched group and vocabulary-matched group of children with NH. Results: Children with CIs, like their peers with NH, demonstrated use of informative verbs to look more quickly to the target word and look less to the phonological competitor. However, children with CIs demonstrated less efficient use of semantic cues relative to their peers with NH, even when matched for vocabulary ability. Conclusions: Children with CIs use semantic prediction to facilitate spoken word recognition but do so to a lesser extent than children with NH. Children with CIs experience challenges in predictive spoken language processing above and beyond limitations from delayed vocabulary development. Children with CIs with better vocabulary ability demonstrate more efficient use of lexical-semantic cues. Clinical interventions focusing on building knowledge of words and their associations may support efficiency of spoken language processing for children with CIs.

Purpose: Previous research shows that shared storybook reading interactions can function as effective speech and language interventions for young children, helping to improve a variety of skills--including word-learning. This study sought to investigate the potential benefits of elaboration of new words during a single storybook reading with preschoolers. Method: Thirty-three typically developing children ages 35-37 months listened to a storybook containing novel words that were either repeated with a definition, repeated with no additional information, or only said once. Their receptive word-learning for these novel words was then evaluated via a preferential looking task. We analyzed children's correct looks to target pictures and compared looking behavior across the three levels of presentation. Results: Results showed that preschoolers demonstrated successful receptive word-learning after a single storybook reading interaction with an adult when target words were repeated, either with or without elaboration. Within this context, elaboration was not required for preschoolers' receptive word-learning. Conclusions: These results support the use of storybook reading with young children as a way to foster early receptive word-learning and highlight the importance of repeated exposure to novel material either with or without additional semantic information.

Hearing words in sentences facilitates word recognition in monolingual children. Many children grow up receiving input in multiple languages -- including exposure to sentences that 'mix' the languages. We explored Spanish-English bilingual toddlers' (n = 24) ability to identify familiar words in three conditions: (i) single word ("ball!"); (ii) same-language sentence ("Where's the ball?"); or (iii) mixed-language sentence ("Dónde está la ball?"). Children successfully identified words across conditions; however, the advantage linked to hearing words in sentences was present only in the same-language condition. This work hence suggests that language mixing plays an important role on bilingual children's ability to recognize spoken words.

Background: This study examined the development of stress sensitivity and its relationship with word reading. Previous research has rarely measured phoneme and stress sensitivity in the same task, making a direct comparison of the contribution between the two in reading development difficult. Methods: Participants were native English-speaking adults and children at ages of 6, 8, and 10 years (N = 24, 22, 22, and 24, respectively). A lexical decision task was used to measure both stress and phoneme sensitivity. Oral vocabulary, phoneme awareness, and word reading were assessed. Results: Stress sensitivity accounted for unique variance in reading over and above vocabulary and phoneme awareness in 6-year-olds. Both adults and children had better phoneme sensitivity than stress sensitivity. Conclusions: These findings highlight the unique contribution of stress sensitivity in reading development. The current study made a novel contribution to studying the relationship between prosody and literacy by utilising a task that is able to assess children's stress and phoneme sensitivity simultaneously.

This retrospective, exploratory investigation examined the types of target words that 66 children with/without word-finding difficulties (WFD) had difficulty naming, and the types of errors they made. Words were studied with reference to lexical factors (LFs) that might influence naming performance: word frequency, familiarity, length, phonotactic probability, and lexical neighborhood. For the most part, LFs similarly affected the word finding of children with/without WFD. Target word frequency predicted word-finding success for both groups, and word substitutions and error patterns were affected by the LFs under study. Children tended to produce substitutions that were shorter and higher in frequency, neighborhood frequency, and phonotactic probability than the target word. LFs also influenced children's error patterns. Low word frequency led to form-related blocked errors for both groups, and low neighborhood frequency predicted form- and segment-related phonologic errors for children with WFD only. Theoretical and practical implications of these preliminary findings are discussed.

Prior work demonstrated that toddlers can learn words from a speaker with a foreign accent and generalize that learning to the native accent when the accented variation does not cross phoneme boundaries. The current study explores the situation in which a vowel in the foreign accent is produced such that it could be confused with a different intended vowel in the native accent. Children were taught two new word-object pairings by a foreign-accented speaker; when vowels were produced similarly across accents, toddlers aged 32 months successfully accommodated a change in accent between training and test; when a novel word contained a vowel that was more affected by accent, toddlers did not later recognize the words in their native accent. This suggests that toddlers may face added difficulty when learning words from speakers of different accents when there is the potential for phonetic confusion across vowels.

There have been many studies examining the differences between infant-directed speech (IDS) and adult-directed speech (ADS). However, investigations asking whether mothers clarify vowel articulation in IDS have reached equivocal findings. Moreover, it is unclear whether maternal speech clarification has any effect on a child's developing language skills. This study examined vowel clarification in mothers' IDS at 0;10-11, 1;6, and 2;0, as compared to their vowel production in ADS. Relationships between vowel space, vowel duration, and vowel variability and child language outcomes at two years were also explored. Results show that vowel space and vowel duration tended to be greater in IDS than in ADS, and that one measure of vowel clarity, a mother's vowel space at 1;6, was significantly related to receptive as well as expressive child language outcomes at two years of age.

Purpose: Normal-hearing (NH) listeners rate normalize, temporarily remapping phonemic category boundaries to account for a talker's speech rate. It is unknown if adults who use auditory prostheses called cochlear implants (CI) can rate normalize, as CIs transmit degraded speech signals to the auditory nerve. Ineffective adjustment to rate information could explain some of the variability in this population's speech perception outcomes. Method: Phonemes with manipulated voice-onset-time (VOT) durations were embedded in sentences with different speech rates. Twenty-three CI and 29 NH participants performed a phoneme identification task. NH participants heard the same unprocessed stimuli as the CI participants or stimuli degraded by a sine vocoder, simulating aspects of CI processing. Results: CI participants showed larger rate normalization effects (6.6 ms) than the NH participants (3.7 ms) and had shallower (less reliable) category boundary slopes. NH participants showed similarly shallow slopes when presented acoustically degraded vocoded signals, but an equal or smaller rate effect in response to reductions in available spectral and temporal information. Conclusion: CI participants can rate normalize, despite their degraded speech input, and show a larger rate effect compared to NH participants. CI participants may particularly rely on rate normalization to better maintain perceptual constancy of the speech signal.

Both the input directed to the child, and the child's ability to process that input, are likely to impact the child's language acquisition. We explore how these factors inter-relate by tracking the relationships among: (a) lexical properties of maternal child-directed speech to prelinguistic (7-month-old) infants (N = 121); (b) these infants' abilities to segment lexical targets from conversational child-directed utterances in an experimental paradigm; and (c) the children's vocabulary outcomes at age 2;0. Both repetitiveness in maternal input and the child's speech segmentation skills at age 0;7 predicted language outcomes at 2;0; moreover, while these factors were somewhat inter-related, they each had independent effects on toddler vocabulary skill, and there was no interaction between the two.

We examined code-switching (CS) in the speech of twenty-four bilingual caregivers when speaking with their 18- to 24-month-old children. All parents CS at least once in a short play session, and some code-switched quite often (over 1/3 of utterances). This CS included both inter-sentential and intra-sentential switches, suggesting that at least some children are frequently exposed to mixed-language sentences. However, we found no evidence that this exposure to CS had any detrimental effect on children's word learning: children's overall vocabulary size did not relate to parental inter-sentential CS behavior, and was positively related to within-sentence CS. Parents often repeated words across their two languages, but this did not appear to increase the likelihood of children having translation equivalents in their vocabulary. In short, parents appear to CS fairly often to young children, even within sentences, but there is no evidence that this delays child lexical acquisition.

Purpose: A new literature has suggested that speech rate can influence the parsing of words quite strongly in speech. The purpose of this study was to investigate differences between younger adults and older adults in the use of context speech rate in word segmentation, given that older adults perceive timing information differently from younger ones. Method: Younger (18-25 years) and older (55-65 years) adults performed a sentence transcription task for sentences that varied in speech rate context (i.e., distal speech rate) and a syntactic cue to the presence of a word boundary. Results: There were no differences between younger and older adults in their use of the distal speech rate cue to word segmentation. Conclusions: The differences previously documented between younger and older adults in their perception of speech rate cues do not necessarily translate to older adults' use of those cues. Older adults' difficulties with compressed speech may arise from problems broader than just speech rate alone.

Fluent speech does not contain obvious breaks to word boundaries, yet there are a number of cues that listeners can use to help them segment the speech stream. Most of these cues have been investigated in isolation from one another. In previous work, Norris, McQueen, Cutler, and Butterfield (1997) suggested that listeners use a Possible Word Constraint when segmenting fluent speech into individual words. This constraint limits the word recognition system to consider only those parsings that could conceivably be words in the language (that is, those that do not strand illegal sequences). The present paper examines how this constraint interacts with other cues to segmentation, such as junctural and allophonic cues and neighborhood probabilities. Segmentation was influenced both by the PWC and by the presence of acoustic cues to juncture, such as the acoustic results of a speaker's intention to produce a particular phoneme as the end of one syllable vs. as the start of another (vuff-apple vs. vuh-fapple). In contrast, segmentation was not affected by the legality of a syllable-final vowel (tense vs. lax), or by the similarity of a sequence to words. This suggests that acoustic cues in the signal play a far larger role in segmentation than do sources of bias from the lexicon, and that probabilistic lexical information from the lexicon (such as neighborhood information) is unlikely to be used in the process of word segmentation.

Infants and toddlers are often spoken to in the presence of background sounds, including speech from other talkers. Prior work has suggested that infants 1 year of age and younger can only recognize speech when it is louder than any distracters in the environment. The present study tests 24-month-olds' ability to understand speech in a multitalker environment. Children were presented with a preferential-looking task in which a target voice told them to find one of two objects. At the same time, multitalker babble was presented as a distracter, at one of four signal-to-noise ratios. Children showed some ability to understand speech and look at the appropriate referent at signal-to-noise ratios as low as -5 dB. These findings suggest that 24-month-olds are better able to selectively attend to an interesting voice in the context of competing distracter voices than are younger infants. There were significant correlations between individual children's performance and their vocabulary size, but only at one of the four noise levels; thus, it does not appear that vocabulary size is the driving factor in children's listening improvement, although it may be a contributing factor to performance in noisy environments. (Contains 1 figure, 1 table, and 2 footnotes.)

We examined how children with and without oral language (word-finding) difficulties (WFD) perform on oral reading (OR) versus silent reading recognition (SRR) tasks when reading the same words and how lexical factors influenced OR accuracy, error patterns, and nature of miscues. Primary-grade students were administered an experimental reading measure. Words were controlled for lexical factors known to influence oral language, such as frequency, lexical neighborhood, familiarity, and phonotactic probability. For learners with WFD, SRR was superior to OR; lexical factors predicted OR success; WF error-patterns emerged in OR; and miscues were higher in frequency, more familiar, and from denser neighborhoods than targets. (Contains 3 figures, 1 table and 6 notes.)

Purpose: The purpose of this study was to investigate whether lexical access in adults who stutter (AWS) differs from that in people who do not stutter. Specifically, the authors examined the role of 3 lexical factors on naming speed, accuracy, and fluency: word frequency, neighborhood density, and neighborhood frequency. If stuttering results from an impairment in lexical access, these factors were hypothesized to differentially affect AWS performance on a confrontation naming task. Method: Twenty-five AWS and 25 normally fluent comparison speakers, matched for age and education, participated in a confrontation naming task designed to explore within-speaker performance on naming accuracy, speed, and fluency based on stimulus word frequency and neighborhood characteristics. Accuracy, fluency, and reaction time (from acoustic waveform analysis) were computed. Results: In general, AWS demonstrated the same effects of lexical factors on their naming as did adults who do not stutter. However, accuracy of naming was reduced for AWS. Stuttering rate was influenced by word frequency but not other factors. Conclusions: Results suggest that AWS could have a fundamental deficit in lexical retrieval, but this deficit is unlikely to be at the level of the word's abstract phonological representation. Implications for further research are discussed.

Although a large literature discusses infants' preference for infant-directed speech (IDS), few studies have examined how this preference might change over time or across listening situations. The work reported here compares infants' preference for IDS while listening in a quiet versus a noisy environment, and across 3 points in development: 4.5 months of age, 9 months of age, and 13 months of age. Several studies have suggested that IDS might help infants to pick out speech in the context of noise (Colombo, Frick, Ryther, Coldren, & Mitchell, 1995; Fernald, 1984; Newman, 2003); this might suggest that infants' preference for IDS would increase in these settings. However, this was not found to be the case; at all 3 ages, infants showed similar advantage (or lack thereof) for IDS as compared to adult-directed speech when presented in noise versus silence. There was, however, a significant interaction across ages: Infants aged 4.5 months showed an overall preference for IDS, whereas older infants did not, despite listening to the same stimuli. The lack of an effect with older infants replicates and extends recent findings by Hayashi, Tamekawa, and Kiritani (2001), suggesting that the variations in fundamental frequency and affect are not sufficient cues to IDS for older infants. (Contains 3 figures, 2 tables, and 4 footnotes.)

This study examined infants' abilities to separate speech from different talkers and to recognize a familiar word (the infant's own name) in the context of noise. In 4 experiments, infants heard repetitions of either their names or unfamiliar names in the presence of background babble. Five-month-old infants listened longer to their names when the target voice was 10 dB, but not 5 dB, more intense than the background. Nine-month-olds likewise failed to identify their names at a 5-dB signal-to-noise ratio, but 13-month-olds succeeded. Thus, by 5 months, infants possess some capacity to selectively attend to an interesting voice in the context of competing distractor voices. However, this ability is quite limited and develops further when infants near 1 year of age.

This study investigated how lexical access in naming tasks (picture naming, naming to open-ended sentences, and naming to category exemplars) might be influenced by different lexical factors during adolescence and adulthood. Participants included 1075 individuals, ranging in age from 12 to 83 years. Lexical factors examined included word frequency and familiarity, age of acquisition, neighborhood density, and phonotactic probability. As expected, each of these factors influenced lexical access, and there was a general trend towards less accurate naming with age. More interestingly, word frequency and neighborhood density both showed larger effects for adolescents than for adults, but then showed constant effects on lexical access throughout adulthood. Phonotactic probability showed constant effects across the lifespan. Effects of word familiarity and age of acquisition interacted with age in adulthood; lexical access of older adults was more greatly affected by a word's familiarity and age of acquisition than was the lexical access of younger adults. These lexical factors impact on adult naming so that words that were learned later in life and which are judged to be less familiar are more difficult to retrieve then their counterparts (words learned earlier and judged to be more familiar) as individuals age. This suggests that age of acquisition and familiarity may play a protective role in adult naming. In contrast, word frequency and form-based properties of words appear to have similar effects throughout adulthood. Implications of these findings for theories of aging and for models of lexical access are discussed. (Contains 5 figures and 3 footnotes.)

Little is known about the acoustic cues infants might use to selectively attend to one talker in the presence of background noise. This study examined the role of talker familiarity as a possible cue. Infants either heard their own mothers (maternal-voice condition) or a different infant's mother (novel-voice condition) repeating isolated words while a female distracter voice spoke fluently in the background. Subsequently, infants heard passages produced by the target voice containing either the familiarized, target words or novel words. Infants in the maternal-voice condition listened significantly longer to the passages containing familiar words; infants in the novel-voice condition showed no preference. These results suggest that infants are able to separate the simultaneous speech of two women when one of the voices is highly familiar to them. However, infants seem to find separating the simultaneous speech of two unfamiliar women extremely difficult.

This retrospective, exploratory investigation examined the types of target words that 30 children with word-finding difficulties (aged 8 to 12 years) had difficulty naming and the types of errors they made on these words. Words were studied with reference to lexical factors that might influence naming performance: word frequency, age of acquisition, familiarity, and lexical neighborhood. Findings indicated that neighborhood density predicted word-finding success, and target word substitutions and error patterns manifested were affected by the lexical factors under study. Students tended to produce substitutions that were higher in frequency, learned earlier, and that resided in neighborhoods of greater density and higher frequency than the target word. Lexical factors also influenced children's error patterns. Neighborhood density predicted form-related errors: Children produced more blocked errors on words from sparse neighborhoods. Word frequency and neighborhood frequency predicted form-segment-related errors as phonologic errors occurred on rare words and words whose neighbors contained lower frequency, uncommon phonological patterns. This important first step in the examination of how lexical factors have an impact on word-finding errors in children suggests that different types of words are more likely to result in failures of lexical access at different stages of processing. Theoretical and practical implications of these preliminary findings are discussed.

Examined mothers' speech to 2-year-old children in both quiet and moderately noisy conditions. Mothers were recorded while teaching their children two words, one of which occurred in the context of other people speaking. Parents used characteristics of infant-directed speech (IDS) to these older children. In addition, many of the prosodic changes typical of IDS were accentuated in noise. (Author/VWL)

Studied the influence of lexical factors, known to impact lexical access in adults, on the word retrieval of children. Participants included 320 typical and atypical language learning children, ranging from 7 to 12 years of age. Lexical factors examined included word frequency, age of acquisition, neighborhood density, neighborhood frequency, and stress pattern. Findings indicated that these factors did influence lexical access in children. (Author/VWL)

Abstract Listeners find it relatively difficult to recognize words that are similar-sounding to other known words. In contrast, when asked to identify spoken nonwords, listeners perform better when the nonwords [...]