What do bilingual infants actually hear? Evaluating measures of language input to bilingual‐learning 10‐month‐olds

Examining how bilingual infants experience their dual language input is important for understanding bilingual language acquisition. To assess these language experiences, researchers typically conduct language interviews with caregivers. However, little is known about the reliability of these parent reports in describing how bilingual children actually experience dual language input. Here, we explored the quantitative nature of dual language input to bilingual infants. Furthermore, we described some of the heterogeneity of bilingual exposure in a sample of French–English bilingual families. Participants were 21 families with a 10‐month‐old infant residing in Montréal, Canada. First, we conducted language interviews with the caregivers. Then, each family completed three full‐day recordings at home using the Language Environment Analysis recording system. Results showed that children’s proportion exposure to each language was consistent across the two measurement approaches, indicating that parent reports are reliable for assessing a bilingual child’s language experiences. Further exploratory analyses revealed three unique findings: (a) there can be considerable variability in the absolute amount of input among infants hearing the same proportion of input, (b) infants can hear different proportions of language input when considering infant‐directed versus overheard speech, (c) proportion of language input can vary by day, depending on who is caring for the infant. We conclude that collecting naturalistic recordings is complementary to parent‐report measures for assessing infant’s language experiences and for establishing bilingual profiles.     

成人言语输入对儿童早期单词获得影响的个案追踪

追踪观察一名婴儿(6~20个月), 分析其中看护者的言语输入特征及婴儿早期词汇获得的发展变化。主要对成人言语输入中动、名词比例、单词在句中的位置、具体环境等因素及婴儿早期动、名词理解和产生等方面进行探讨。结果显示, 成人言语输入中动词比例显著高于名词, 更多动词位于句首或句尾使得主语和宾语省略; 同时, 这种动词优势的输入特征促进儿童早期动词获得, 使得婴儿早期语言样本中动、名词理解相对比例与成人言语输入一致。这一结果表明, 婴儿词汇发展初期就已经利用言语或社会线索, 同时这种早期词汇组成中较高的动词比例进一步支持“名词优势”理论存在跨语言差异     

Word frequency as a cue for identifying function words in infancy

While content words (e.g., ‘dog’) tend to carry meaning, function words (e.g., ‘the’) mainly serve syntactic purposes. Here, we ask whether 17-month old infants can use one language–universal cue to identify function word candidates: their high frequency of occurrence. In Experiment 1, infants listened to a series of short, naturally recorded sentences in a foreign language (i.e., in French). In these sentences, two determiners appeared much more frequently than any content word. Following this, infants were presented with a visual object, and simultaneously with a word pair composed of a determiner and a noun. Results showed that infants associated the object more strongly with the infrequent noun than with the frequent determiner. That is, when presented with both the old object and a novel object, infants were more likely to orient towards the old object when hearing a label with a new determiner and the old noun compared to a label with a new noun and the old determiner. In Experiment 2, infants were tested using the same procedure as in Experiment 1, but without the initial exposure to French sentences. Under these conditions, infants did not preferentially associate the object with nouns, suggesting that the preferential association between nouns and objects does not result from specific acoustic or phonological properties. In line with various biases and heuristics involved in acquiring content words, we provide the first direct evidence that infants can use distributional cues, especially the high frequency of occurrence, to identify potential function words.     

Enhanced gaze‐following behavior in Deaf infants of Deaf parents

Gaze following plays a role in parent–infant communication and is a key mechanism by which infants acquire information about the world from social input. Gaze following in Deaf infants has been understudied. Twelve Deaf infants of Deaf parents (DoD) who had native exposure to American Sign Language (ASL) were gender‐matched and age‐matched (±7 days) to 60 spoken‐language hearing control infants. Results showed that the DoD infants had significantly higher gaze‐following scores than the hearing infants. We hypothesize that in the absence of auditory input, and with support from ASL‐fluent Deaf parents, infants become attuned to visual‐communicative signals from other people, which engenders increased gaze following. These findings underscore the need to revise the ‘deficit model’ of deafness. Deaf infants immersed in natural sign language from birth are better at understanding the signals and identifying the referential meaning of adults’ gaze behavior compared to hearing infants not exposed to sign language. Broader implications for theories of social‐cognitive development are discussed. A video abstract of this article can be viewed at https://youtu.be/QXCDK_CUmAI     

Content words in Hebrew child-directed speech

The goal of the study was to examine whether the ‘noun-bias’ phenomenon, which exists in the lexicon of Hebrew-speaking children, also exists in Hebrew child-directed speech (CDS) as well as in Hebrew adult-directed speech (ADS). In addition, we aimed to describe the use of the different classes of content words in the speech of Hebrew-speaking parents to their children at different ages compared to the speech of parents to adults (ADS). Thirty infants (age range 8:5–33 months) were divided into three stages according to age: pre-lexical, single-word, and early grammar. The ADS corpus included 18 Hebrew-speaking parents of children at the same three stages of language development as in the CDS corpus. The CDS corpus was collected from parent–child dyads during naturalistic activities at home: mealtime, bathing, and play. The ADS corpus was collected from parent–experimenter interactions including the parent watching a video and then being interviewed by the experimenter. 200 utterances of each sample were transcribed, coded for types and tokens and analyzed quantitatively and qualitatively. Results show that in CDS, when speaking to infants of all ages, parents’ use of types and tokens of verbs and nouns was similar and significantly higher than their use of adjectives or adverbs. In ADS, however, verbs were the main lexical category used by Hebrew-speaking parents in both types and tokens. It seems that both the properties of the input language (e.g. the pro-drop parameter) and the interactional styles of the caregivers are important factors that may influence the high presence of verbs in Hebrew-speaking parents’ ADS and CDS. The negative correlation between the widespread use of verbs in the speech of parents to their infants and the ‘noun-bias’ phenomenon in the Hebrew-child lexicon will be discussed in detail.     

What Do North American Babies Hear? A large‐scale cross‐corpus analysis

A range of demographic variables influences how much speech young children hear. However, because studies have used vastly different sampling methods, quantitative comparison of interlocking demographic effects has been nearly impossible, across or within studies. We harnessed a unique collection of existing naturalistic, day‐long recordings from 61 homes across four North American cities to examine language input as a function of age, gender, and maternal education. We analyzed adult speech heard by 3‐ to 20‐month‐olds who wore audio recorders for an entire day. We annotated speaker gender and speech register (child‐directed or adult‐directed) for 10,861 utterances from female and male adults in these recordings. Examining age, gender, and maternal education collectively in this ecologically valid dataset, we find several key results. First, the speaker gender imbalance in the input is striking: children heard 2–3× more speech from females than males. Second, children in higher‐maternal education homes heard more child‐directed speech than those in lower‐maternal education homes. Finally, our analyses revealed a previously unreported effect: the proportion of child‐directed speech in the input increases with age, due to a decrease in adult‐directed speech with age. This large‐scale analysis is an important step forward in collectively examining demographic variables that influence early development, made possible by pooled, comparable, day‐long recordings of children's language environments. The audio recordings, annotations, and annotation software are readily available for reuse and reanalysis by other researchers.     

Piecing together numerical language: children's use of default units in early counting and quantification

When asked to ‘find three forks’, adult speakers of English use the noun ‘fork’ to identify units for counting. However, when number words (e.g. three) and quantifiers (e.g. more, every) are used with unfamiliar words (‘Give me three blickets’) noun‐specific conceptual criteria are unavailable for picking out units. This poses a problem for young children learning language, who begin to use quantifiers and number words by age 2, despite knowing a relatively small number of nouns. Without knowing how individual nouns pick out units of quantification – e.g. what counts as a blicket– how could children decide whether there are three blickets or four? Three experiments suggest that children might solve this problem by assigning ‘default units’ of quantification to number words, quantifiers, and number morphology. When shown objects that are broken into arbitrary pieces, 4‐year‐olds in Experiment 1 treated pieces as units when counting, interpreting quantifiers, and when using singular–plural morphology. Experiment 2 found that although children treat object‐hood as sufficient for quantification, it is not necessary. Also sufficient for individuation are the criteria provided by known nouns. When two nameable things were glued together (e.g. two cups), children counted the glued things as two. However, when two arbitrary pieces of an object were put together (e.g. two parts of a ball), children counted them as one, even if they had previously counted the pieces as two. Experiment 3 found that when the pieces of broken things were nameable (e.g. wheels of a bicycle), 4‐year‐olds did not include them in counts of whole objects (e.g. bicycles). We discuss the role of default units in early language acquisition, their origin in acquisition, and how children eventually acquire an adult semantics identifying units of quantification.     

Parent coaching at 6 and 10 months improves language outcomes at 14 months: A randomized controlled trial

Previous studies reveal an association between particular features of parental language input and advances in children's language learning. However, it is not known whether parent coaching aimed to enhance specific input components would (a) successfully increase these components in parents' language input and (b) result in concurrent increases in children's language development. The present randomized controlled trial assigned families of typically developing 6‐month‐old infants to Intervention (parent coaching) and Control (no coaching) groups. Families were equivalent on socioeconomic status, infants' gender, and infants' age. Parent coaching took place when infants were 6 and 10 months of age, and included quantitative and qualitative linguistic feedback on the amount of child‐directed speech, back‐and‐forth interactions, and parentese speech style. These variables were derived from each family's first‐person LENA recordings at home. Input variables and infant language were measured at 6, 10, and 14 months. Parent coaching significantly enhanced language input as measured by two social interaction variables: percentage of speech directed to the child and percentage of parentese speech. These two variables were correlated, and were both related to growth in infant babbling between 6 and 14 months. Intervention infants showed greater growth in babbling than Control infants. Furthermore, at 14 months, Intervention infants produced significantly more words than Control infants, as indicated by LENA recordings and parent report via the MacArthur‐Bates Communicative Developmental Inventory. Together, these results indicate that parent coaching can enrich specific aspects of parental language input, and can immediately and positively impact child language outcomes. A video abstract of this article can be viewed at: https://youtu.be/7wqR28gPiwo     

儿童早期词汇获得的词类差

儿童早期词汇获得存在词类差异,很多语言中名词比例都要高于其他词类,因此一些研究者提出“名词优势”理论。但是,一些对汉语和韩语的研究发现,儿童早期获得的动词比例与名词没有显著差异,甚至高于名词,同时汉语和韩语动词比例也远大于英语动词比例。针对不同语言儿童早期获得的动、名词比例差异现象,研究者认为语言结构特征和成人对孩子的言语输入可以解释不同语言儿童早期词汇中动、名词比例的差异,其中成人言语中词类的频率、单词位置、词形变化复杂性和语用等因素都会影响儿童早期词汇获得。此外,不同的词汇测量方法、观察情境、词类定义、词汇量水平、单词理解与说出也会造成不同研究结果之间的差异     

All words are not created equal: expectations about word length guide infant statistical learning

Infants have been described as ‘statistical learners’ capable of extracting structure (such as words) from patterned input (such as language). Here, we investigated whether prior knowledge influences how infants track transitional probabilities in word segmentation tasks. Are infants biased by prior experience when engaging in sequential statistical learning? In a laboratory simulation of learning across time, we exposed 9- and 10-month-old infants to a list of either disyllabic or trisyllabic nonsense words, followed by a pause-free speech stream composed of a different set of disyllabic or trisyllabic nonsense words. Listening times revealed successful segmentation of words from fluent speech only when words were uniformly disyllabic or trisyllabic throughout both phases of the experiment. Hearing trisyllabic words during the pre-exposure phase derailed infants’ abilities to segment speech into disyllabic words, and vice versa. We conclude that prior knowledge about word length equips infants with perceptual expectations that facilitate efficient processing of subsequent language input.     

Infants prefer motionese to adult‐directed action

In two studies, we investigated infants’ preference for infant‐directed (ID) action or ‘motionese’ ( Brand, Baldwin & Ashburn, 2002 ) relative to adult‐directed (AD) action. In Study 1, full‐featured videos were shown to 32 6‐ to 8‐month‐olds, who demonstrated a strong preference for ID action. In Study 2, infants at 6–8 months (n= 28) and 11–13 months (n= 24) were shown either standard ID and AD clips, or clips in which demonstrators’ faces were blurred to obscure emotional and eye‐gaze information. Across both ages, infants showed evidence of preferring ID to AD action, even when faces were blurred. Infants did not have a preference for still‐frame images of the demonstrators, indicating that the ID preference arose from action characteristics, not demonstrators’ general appearance. These results suggest that motionese enhances infants’ attention to action, possibly supporting infants’ learning.     

从词汇量角度再探汉语婴儿是否存在“名词优势”

本研究采用交叉聚合设计,从词汇量角度考察了两岁左右汉语婴儿是否存在“名词优势”现象。在前测中,110名18、24和30个月龄的儿童接受了PCDI量表和父母问卷调查;6个月后,18个月和24个月组接受了PCDI量表的再测。本研究将“名词优势效应”定义为“（名词得分–动词得分）/词汇总分”（以k值表示）,将名词得分大于动词得分者定义为“名词优势者”。结果发现：（1）从各年龄组均值来看,18个月组名词优势效应较小（k = .07）,24及30个月组名词优势效应显著增大（k = .11~.19）。（2）从个体水平来看,18个月组名词优势者和动词优势者约各占50%（p > .05）,而24、30个月组中81~100%的儿童都是名词优势者。该结果提示,以往不同研究之间的分歧可能是由于名词优势是随年龄而动态变化的。     

The origins and evolution of links between word learning and conceptual organization: new evidence from 11‐month‐olds

How do infants map words to their meaning? How do they discover that different types of words (e.g. noun, adjective) refer to different aspects of the same objects (e.g. category, property)? We have proposed that (1) infants begin with a broad expectation that novel open‐class words (both nouns and adjectives) highlight commonalities (both category‐ and property‐based) among objects, and that (2) this initial expectation is subsequently fine‐tuned through linguistic experience. We examine the first part of this proposal, asking whether 11‐month‐old infants can construe the very same set of objects (e.g. four purple animals) either as members of an object category (e.g. animals) or as embodying a salient object property (e.g. four purple things), and whether naming (with count nouns vs. adjectives) differentially influences their construals. Results support the proposal. Infants treated novel nouns and adjectives identically, mapping both types of words to both category‐ and property‐based commonalities among objects.     

The Other Accent Effect in Talker Recognition: Now You See It,Now You Don't

The existence of the Language Familiarity Effect (LFE), where talkers of a familiar language are easier to identify than talkers of an unfamiliar language, is well-documented and uncontroversial. However, a closely related phenomenon known as the Other Accent Effect (OAE), where accented talkers are more difficult to recognize, is less well understood. There are several possible explanations for why the OAE exists, but to date, little data exist to adjudicate differences between them. Here, we begin to address this issue by directly comparing listeners’ recognition of talkers who speak in different types of accents, and by examining both the LFE and OAE in the same set of listeners. Specifically, Canadian English listeners were tested on their ability to recognize talkers within four types of voice line-ups: Canadian English talkers, Australian English talkers, Mandarin-accented English talkers, and Mandarin talkers. We predicted that the OAE would be present for talkers of Mandarin-accented English but not for talkers of Australian English—which is precisely what we observed. We also observed a disconnect between listeners’ confidence and performance across different types of accents; that is, listeners performed equally poorly with Mandarin and Mandarin-accented talkers, but they were more confident with their performance with the latter group of talkers. The present findings set the stage for further investigation into the nature of the OAE by exploring a range of potential explanations for the effect, and introducing important implications for forensic scientists’ evaluation of ear witness testimony.     

Grounding by Attention Simulation in Peripersonal Space: Pupils Dilate to Pinch Grip But Not Big Size Nominal Classifier

Grammatical categories represent implicit knowledge, and it is not known if such abstract linguistic knowledge can be continuously grounded in real‐life experiences, nor is it known what types of mental states can be simulated. A former study showed that attention bias in peripersonal space (PPS) affects reaction times in grammatical congruency judgments of nominal classifiers, suggesting that simulated semantics may include reenactment of attention. In this study, we contrasted a Chinese nominal classifier used with nouns denoting pinch grip objects with a classifier for nouns with big object referents in a pupil dilation experiment. Twenty Chinese native speakers read grammatical and ungrammatical classifier‐noun combinations and made grammaticality judgment while their pupillary responses were measured. It was found that their pupils dilated significantly more to the pinch grip classifier than to the big object classifier, indicating attention simulation in PPS. Pupil dilations were also significantly larger with congruent trials on the whole than in incongruent trials, but crucially, congruency and classifier semantics were independent of each other. No such effects were found in controls.     

Modality effects in compounding with English inflectional morphology

The treatment of plural morphemes in English noun–noun compounds is significant because it provides a test case for competing theories of language acquisition and representation. Even when the first noun in a compound refers to plural items, native speakers frequently use the singular form ( Murphy, 2000 ). Sometimes, they will use the irregular plural form (‘mice chaser’) but very rarely are regular plurals (‘rats chaser’) used as the first noun in a compound. This effect has been found with native English‐ speaking children ( Gordon, 1985 ; Nicoladis, 2000 ; Oetting & Rice, 1993 ; van der Lely & Christian, 2000 ); native English‐speaking teenagers ( van der Lely & Christian, 2000 ); and native English‐speaking adults ( Lardiere & Schwartz, 1997 ; Murphy, 2000 ). The apparent dissociation between regular and irregular plurals (i.e. that irregular plurals are included before a second noun but regular plurals are almost never included before a second noun) is thought to be due to innate morphological constraints ( Marcus, Brinkmann, Clahsen, Weise, & Pinker, 1995 ). Such constraints predict that all items of regular morphology should be treated differently from all items of irregular morphology by language users in all situations. However, if external factors such as input and response modality affect the number of plurals included in compounds, then this questions the internal constraint‐based explanations of compounding and encourages investigation of how external factors might influence the number of plurals included in compounds.     

Effects of testing on subsequent re‐encoding and long‐term forgetting of action‐relevant materials: On the influence of recall type

Testing one's memory of previously studied information reduces the rate of forgetting, compared to restudy. However, little is known about how this direct testing effect applies to action phrases (e.g., “wash the car”) – a learning material relevant to everyday memory. As action phrases consist of two different components, a verb (e.g., “wash”) and a noun (e.g., “car”), testing can either be implemented as noun‐cued recall of verbs or verb‐cued recall of nouns, which may differently affect later memory performance. In the present study, we investigated the effect of testing for these two recall types, using verbally encoded action phrases as learning materials. Results showed that repeated study–test practice, compared to repeated study–restudy practice, decreased the forgetting rate across 1 week to a similar degree for both noun‐cued and verb‐cued recall types. However, noun‐cued recall of verbs initiated more new subsequent learning during the first restudy, compared to verb‐cued recall of nouns. The study provides evidence that testing has benefits on both subsequent restudy and long‐term retention of action‐relevant materials, but that these benefits are differently expressed with testing via noun‐cued versus verb‐cued recall.     

Dissecting the time course of person recognition in natural viewing environments

Person recognition often unfolds over time and distance as a person approaches, with the quality of identity information from faces, bodies, and motion in constant flux. Participants were familiarized with identities using close‐up and distant videos. Recognition was tested with videos of people approaching from a distance. We varied the timing of prompted responses in the test videos, the amount of video seen, and whether the face, body, or whole person was visible. A free response condition was also included to allow participants to respond when they felt ‘confident’. The pattern of accuracy across conditions indicated that recognition judgments were based on the most recently available information, with no contribution from qualitatively diverse and statistically useful person cues available earlier in the video. Body recognition was stable across viewing distance, whereas face recognition improved with proximity. The body made an independent contribution to recognition only at the farthest distance tested. Free response latencies indicated meta‐knowledge of the optimal proximity for recognition from faces versus bodies. Notably, response bias varied strongly as a function of participants’ expectation about whether closer proximity video was forthcoming. These findings lay the groundwork for developing person recognition theories that generalize to natural viewing environments.     

CCTV on trial: Matching video images with the defendant in the dock

The experiments reported in this paper investigated simultaneous identity matching of unfamiliar people physically present in person with moving video images typical of that captured by closed circuit television (CCTV). This simulates the decision faced by a jury in court when the identity of somebody caught on CCTV is disputed. Namely, ‘is the defendant in the dock the person depicted in video’? In Experiment 1, the videos depicted medium‐range views of a number of actor ‘culprits’. Experiment 2 used similar quality images taken a year previously, some of which showed the culprits in disguise. Experiment 3 utilised high‐quality close‐up video images. It was consistently found that in both culprit‐present and culprit‐absent videos and in optimal conditions, matching the identity of a person in video can be highly susceptible to error. Copyright © 2008 John Wiley & Sons, Ltd.