Is vision necessary for the timely acquisition of language-specific patterns in co-speech gesture and their lack in silent gesture?

Blind adults display language-specificity in their packaging and ordering of events in speech. These differences affect the representation of events in co-speech gesture-gesturing with speech-but not in silent gesture-gesturing without speech. Here we examine when in development blind children begin to show adult-like patterns in co-speech and silent gesture. We studied speech and gestures produced by 30 blind and 30 sighted children learning Turkish, equally divided into 3 age groups: 5-6, 7-8, 9-10 years. The children were asked to describe three-dimensional spatial event scenes (e.g., running out of a house) first with speech, and then without speech using only their hands. We focused on physical motion events, which, in blind adults, elicit cross-linguistic differences in speech and co-speech gesture, but cross-linguistic similarities in silent gesture. Our results showed an effect of language on gesture when it was accompanied by speech (co-speech gesture), but not when it was used without speech (silent gesture) across both blind and sighted learners. The language-specific co-speech gesture pattern for both packaging and ordering semantic elements was present at the earliest ages we tested the blind and sighted children. The silent gesture pattern appeared later for blind children than sighted children for both packaging and ordering. Our findings highlight gesture as a robust and integral aspect of the language acquisition process at the early ages and provide insight into when language does and does not have an effect on gesture, even in blind children who lack visual access to gesture. RESEARCH HIGHLIGHTS: Gestures, when produced with speech (i.e., co-speech gesture), follow language-specific patterns in event representation in both blind and sighted children. Gestures, when produced without speech (i.e., silent gesture), do not follow the language-specific patterns in event representation in both blind and sighted children. Language-specific patterns in speech and co-speech gestures are observable at the same time in blind and sighted children. The cross-linguistic similarities in silent gestures begin slightly later in blind children than in sighted children.

Gesture's Role in the Communication of Adults With Different Types of Aphasia.

PURPOSE: Adults with aphasia gesture more than adults without aphasia. However, less is known about the role of gesture in different discourse contexts for individuals with different types of aphasia. In this study, we asked whether patterns of speech and gesture production of individuals with aphasia vary by aphasia and discourse type and also differ from the speech and gestures produced by adults without aphasia. METHOD: We compared the amount, diversity, and complexity of speech and gesture production in adults with anomic or Broca's aphasia and adults with no aphasia (n = 20/group) in their first- versus third-person narratives. RESULTS: Adults with Broca's aphasia showed the lowest performance in their amount, diversity, and complexity of speech production, followed by adults with anomic aphasia and adults without aphasia. This pattern was reversed for gesture production. Speech and gesture production also varied by discourse context. Adults with either type of aphasia used a lower amount of and less diverse speech in third-person than in first-person narratives; this pattern was also reversed for gesture production. CONCLUSIONS: Overall, our results provide evidence for a compensatory role of gesture in aphasia communication. Adults with Broca's aphasia, who showed the greatest speech production difficulties, also relied most on gesture, and this pattern was particularly pronounced in the third-person narrative context.

When Gestures Do or Do Not Follow Language-Specific Patterns of Motion Expression in Speech: Evidence from Chinese, English and Turkish.

Speakers of different languages (e.g., English vs. Turkish) show a binary split in how they package and order components of a motion event in speech and co-speech gesture but not in silent gesture. In this study, we focused on Mandarin Chinese, a language that does not follow the binary split in its expression of motion in speech, and asked whether adult Chinese speakers would follow the language-specific speech patterns in co-speech but not silent gesture, thus showing a pattern akin to Turkish and English adult speakers in their description of animated motion events. Our results provided evidence for this pattern, with Chinese-as well as English and Turkish-speakers following language-specific patterns in speech and co-speech gesture but not in silent gesture. Our results provide support for the "thinking-for-speaking" account, namely that language influences thought only during online, but not offline, production of speech.

Identifying Patterns of Similarities and Differences between Gesture Production and Comprehension in Autism and Typical Development.

Production and comprehension of gesture emerge early and are key to subsequent language development in typical development. Compared to typically developing (TD) children, children with autism spectrum disorders (ASD) exhibit difficulties and/or differences in gesture production. However, we do not yet know if gesture production either shows similar patterns to gesture comprehension across different ages and learners, or alternatively, lags behind gesture comprehension, thus mimicking a pattern akin to speech comprehension and production. In this study, we focus on the gestures produced and comprehended by a group of young TD children and children with ASD-comparable in language ability-with the goal to identify whether gesture production and comprehension follow similar patterns between ages and between learners. We elicited production of gesture in a semi-structured parent-child play and comprehension of gesture in a structured experimenter-child play across two studies. We tested whether young TD children (ages 2-4) follow a similar trajectory in their production and comprehension of gesture (Study 1) across ages, and if so, whether this alignment remains similar for verbal children with ASD (M age = 5 years), comparable to TD children in language ability (Study 2). Our results provided evidence for similarities between gesture production and comprehension across ages and across learners, suggesting that comprehension and production of gesture form a largely integrated system of communication.

The Time is at Hand: Literacy Predicts Changes in Children's Gestures About Time.

The metaphorical motion of time can be expressed in gesture along either a sagittal axis-with the future ahead and past behind the speaker, or a lateral axis-with the past to the left and future to the right of the speaker (Casasanto & Jasmin in CL 23(4): 643-674, 2012). Adult English speakers, when gesturing about time, show a preference for lateral gestures with left-to-right directionality, consistent with the directionality of the reading-writing system in English (Casasanto & Jasmin in CL 23(4): 643-674, 2012). In this study, we asked how early children would show a preference for left-to-right lateral gestures and whether literacy skills would predict the production of such gestures. Our findings showed developmental changes in both the orientation and directionality of children's gestures about time. Children increased their production of left-to-right lateral gestures over time, with a shift around ages 7-8. More importantly, literacy predicted children's production of such lateral gestures. Overall, these results suggest that the orientation and directionality of children's metaphorical gestures about time follow a developmental pattern that is largely influenced by changes in literacy.

Effect of sex and dyad composition on speech and gesture development of singleton and twin children.

Children's early vocabulary shows sex differences - with boys having smaller vocabularies than age-comparable girls - a pattern that becomes evident in both singletons and twins. Twins also use fewer words than their singleton peers. However, we know relatively less about sex differences in early gesturing in singletons or twins, and also how singletons and twins might differ in their early gesture use. We examine the patterns of speech and gesture production of singleton and twin children, ages 0;10-to-3;4, during structured parent-child play. Boys and girls - singleton or twin - were similar in speech and gesture production, but singletons used a greater amount and diversity of speech and gestures than twins. There was no effect of twin dyad type (boy-boy, girl-girl, boy-girl) on either speech or gesture production. These results confirm earlier research showing close integration between gesture and speech in singletons in early language development, and further extend these patterns to twin children.

Cross-linguistic transfer in Turkish-English bilinguals' descriptions of motion events.

Languages differ in how they express motion: Languages like English prefer to conflate manner and path into the same clause and express both elements frequently while languages like Turkish prefer to express these elements separately, with a greater preference for the expression of path of motion. While typological patterns are well-established for monolingual speakers of a variety of languages, relatively less is known about motion expression in bilingual speakers. The current study examined the packaging (expressing each element in separate clauses or within the same clause) and lexical choices (amount and diversity of manner and path verbs) for motion expression in monolingual speakers of Turkish or English and advanced Turkish (L1)-English (L2) bilinguals in a narrative elicitation task. Bilinguals were successful in attaining many English-like patterns of expression in their L2 English but also showed some packaging and lexical choices that were intermediate between English and Turkish monolinguals-thus providing evidence of an L1-to-L2 cross-linguistic effect. Subtle effects of L2 on L1 were also found in bilinguals' lexical choices for the expression of motion in their L1 Turkish. Altogether, our results demonstrate bi-directional transfer effects of learning a typologically distinct language in advanced Turkish-English bilinguals.

Semantic P600-but not N400-effects index crosslinguistic variability in speakers' expectancies for expression of motion.

The expression of motion shows strong crosslinguistic variability; however, less is known about speakers' expectancies for lexicalizations of motion at the neural level. We examined event-related brain potentials (ERPs) in native English or Spanish speakers while they read grammatical sentences describing animations involving manner and path components of motion that did or did not violate language-specific patterns of expression. ERPs demonstrated different expectancies between speakers: Spanish speakers showed higher expectancies for motion verbs to encode path and English speakers showed higher expectancies for motion verbs to encode manner followed by a secondary path expression. Interestingly, grammatical but infrequent motion expressions (manner verbs in Spanish, path verbs and secondary manner expressions in English) elicited semantic P600 rather than the expected N400 effects-with or without post-N400 positivities-that are typically associated with semantic processing. Overall, our findings provide the first empirical evidence for the effect of crosslinguistic variation in processing motion event descriptions at the neural level.

Early Lateralization of Gestures in Autism: Right-Handed Points Predict Expressive Language.

Children with autism spectrum disorder (ASD) produce fewer deictic gestures, accompanied by delays/deviations in speech development, compared to typically-developing (TD) children. We ask whether children with ASD-like TD children-show right-hand preference in gesturing and whether right-handed gestures predict their vocabulary size in speech. Our analysis of handedness in gesturing in children with ASD (n = 23, Mage = 30-months) and with TD (n = 23, Mage = 18-months) during mother-child play showed a right-hand preference for TD children-but not for children with ASD. Nonetheless, right-handed deictic gestures predicted expressive vocabulary 1 year later in both children with ASD and with TD. Handedness for gesture, both hand preference and amount of right-handed pointing, may be an important indicator of language development in autism and typical development.

Do parents provide a helping hand to vocabulary development in bilingual children?

Monolingual children identify referents uniquely in gesture before they do so with words, and parents translate these gestures into words. Children benefit from these translations, acquiring the words that their parents translated earlier than the ones that are not translated. Are bilingual children as likely as monolingual children to identify referents uniquely in gesture; and do parental translations have the same positive impact on the vocabulary development of bilingual children? Our results showed that the bilingual children - dominant in English or in Spanish - were as likely as monolingual children to identify referents uniquely in gesture. More importantly, the unique gestures, when translated into words by the parents, were as likely to enter bilingual and monolingual children's speech - independent of language dominance. Our results suggest that parental response to child gesture plays as crucial of a role in the vocabulary development of bilingual children as it does in monolingual children.

Do Children Understand Iconic Gestures About Events as Early as Iconic Gestures About Entities?

Children can understand iconic co-speech gestures that characterize entities by age 3 (Stanfield et al. in J Child Lang 40(2):1-10, 2014; e.g., "I'm drinking" [Formula: see text] tilting hand in C-shape to mouth as if holding a glass). In this study, we ask whether children understand co-speech gestures that characterize events as early as they do so for entities, and if so, whether their understanding is influenced by the patterns of gesture production in their native language. We examined this question by studying native English speaking 3- to 4 year-old children and adults as they completed an iconic co-speech gesture comprehension task involving motion events across two studies. Our results showed that children understood iconic co-speech gestures about events at age 4, marking comprehension of gestures about events one year later than gestures about entities. Our findings also showed that native gesture production patterns influenced children's comprehension of gestures characterizing such events, with better comprehension for gestures that follow language-specific patterns compared to the ones that do not follow such patterns-particularly for manner of motion. Overall, these results highlight early emerging abilities in gesture comprehension about motion events.

Do Parents Model Gestures Differently When Children's Gestures Differ?

Children with autism spectrum disorder (ASD) or with Down syndrome (DS) show diagnosis-specific differences from typically developing (TD) children in gesture production. We asked whether these differences reflect the differences in parental gesture input. Our systematic observations of 23 children with ASD and 23 with DS (Mages = 2;6)-compared to 23 TD children (Mage = 1;6) similar in expressive vocabulary-showed that across groups children and parents produced similar types of gestures and gesture-speech combinations. However, only children-but not their parents-showed diagnosis-specific variability in how often they produced each type of gesture and gesture-speech combination. These findings suggest that, even though parents model gestures similarly, the amount with which children produce each type largely reflects diagnosis-specific abilities.

Type of iconicity influences children's comprehension of gesture.

Children produce iconic gestures conveying action information earlier than the ones conveying attribute information (Özçaliskan, Gentner, & Goldin-Meadow, 2014). In this study, we ask whether children's comprehension of iconic gestures follows a similar pattern, also with earlier comprehension of iconic gestures conveying action. Children, ages 2-4years, were presented with 12 minimally-informative speech+iconic gesture combinations, conveying either an action (e.g., open palm flapping as if bird flying) or an attribute (e.g., fingers spread as if bird's wings) associated with a referent. They were asked to choose the correct match for each gesture in a forced-choice task. Our results showed that children could identify the referent of an iconic gesture conveying characteristic action earlier (age 2) than the referent of an iconic gesture conveying characteristic attribute (age 3). Overall, our study identifies ages 2-3 as important in the development of comprehension of iconic co-speech gestures, and indicates that the comprehension of iconic gestures with action meanings is easier than, and may even precede, the comprehension of iconic gestures with attribute meanings.

Correction to: Parents' Translations of Child Gesture Facilitate Word Learning in Children with Autism, Down Syndrome and Typical Development.

The original version of the article unfortunately contained mistake in the "Methods/Participants" section (p. 224) as "[M TD = 168.26 (SD = 125.18) vs. M AU = 172.91 (SD = 195.88) vs. M DS = 145.43 (SD = 88.78); Kruskal-Wallis, χ 2(2) = 2.42, p = .30], and for word types [M TD = 28.43 (SD = 26.89) vs. M AU = 39.65 (SD = 49.07) vs. M DS = 18.35 (SD = 22.78); χ 2(2) = 3.15, p = .21]''. The correct text is given below: "[M TD = 51.91 (SD = 59.68) vs. M AU = 74.43 (SD = 116.01) vs. M DS = 25.26 (SD = 39.39); Kruskal-Wallis, χ 2(2) = 3.39, p = .18], and for word types [M TD = 18.48 (SD = 20.51) vs. M AU = 24.74 (SD = 32.98) vs. M DS  = 11.22 (SD = 18.87); χ 2(2) = 3.58, p = .17]"..

Blind Speakers Show Language-Specific Patterns in Co-Speech Gesture but Not Silent Gesture.

Sighted speakers of different languages vary systematically in how they package and order components of a motion event in speech. These differences influence how semantic elements are organized in gesture, but only when those gestures are produced with speech (co-speech gesture), not without speech (silent gesture). We ask whether the cross-linguistic similarity in silent gesture is driven by the visuospatial structure of the event. We compared 40 congenitally blind adult native speakers of English or Turkish (20/language) to 80 sighted adult speakers (40/language; half with, half without blindfolds) as they described three-dimensional motion scenes. We found an effect of language on co-speech gesture, not on silent gesture-blind speakers of both languages organized their silent gestures as sighted speakers do. Humans may have a natural semantic organization that they impose on events when conveying them in gesture without language-an organization that relies on neither visuospatial cues nor language structure.

Do Verbal Children with Autism Comprehend Gesture as Readily as Typically Developing Children?

Gesture comprehension remains understudied, particularly in children with autism spectrum disorder (ASD) who have difficulties in gesture production. Using a novel gesture comprehension task, Study 1 examined how 2- to 4-year-old typically-developing (TD) children comprehend types of gestures and gesture-speech combinations, and showed better comprehension of deictic gestures and reinforcing gesture-speech combinations than iconic/conventional gestures and supplementary gesture-speech combinations at each age. Study 2 compared verbal children with ASD to TD children, comparable in receptive language ability, and showed similar patterns of comprehension in each group. Our results suggest that children comprehend deictic gestures and reinforcing gesture-speech combinations better than iconic/conventional gestures and supplementary combinations-a pattern that remains robust across different ages within TD children and children with ASD.

Who Did What to Whom? Children Track Story Referents First in Gesture.

Children achieve increasingly complex language milestones initially in gesture or in gesture+speech combinations before they do so in speech, from first words to first sentences. In this study, we ask whether gesture continues to be part of the language-learning process as children begin to develop more complex language skills, namely narratives. A key aspect of narrative development is tracking story referents, specifying who did what to whom. Adults track referents primarily in speech by introducing a story character with a noun phrase and then following the same referent with a pronoun-a strategy that presents challenges for young children. We ask whether young children can track story referents initially in communications that combine gesture and speech by using character viewpoint in gesture to introduce new story characters, before they are able to do so exclusively in speech using nouns followed by pronouns. Our analysis of 4- to 6-year-old children showed that children introduced new characters in gesture+speech combinations with character viewpoint gestures at an earlier age than conveying the same referents exclusively in speech with the use of nominal phrases followed by pronouns. Results show that children rely on viewpoint in gesture to convey who did what to whom as they take their first steps into narratives.

Early gesture provides a helping hand to spoken vocabulary development for children with autism, Down syndrome and typical development.

Typically developing (TD) children refer to objects uniquely in gesture (e.g., point at cat) before they produce verbal labels for these objects ("cat"; Bates et al., 1979). The onset of such gestures predicts the onset of similar spoken words, showing a strong positive relation between early gestures and early words (Iverson & Goldin-Meadow, 2005). We ask whether gesture plays the same door-opening role in word learning for children with autism spectrum disorder (ASD) and Down syndrome (DS), who show delayed vocabulary development and who differ in the strength of gesture production. To answer this question, we observed 23 18-month-old TD children, 23 30-month-old children with ASD and 23 30-month-old children with DS five times over a year during parent-child interactions. Children in all three groups initially expressed a greater proportion of referents uniquely in gesture than in speech. Many of these unique gestures subsequently entered children's spoken vocabularies within a year-a pattern that was slightly less robust for children with DS, whose word production was the most markedly delayed. These results indicate that gesture is as fundamental to vocabulary development for children with developmental disorders as it is for TD children.

Is Seeing Gesture Necessary to Gesture Like a Native Speaker?

Speakers of all languages gesture, but there are differences in the gestures that they produce. Do speakers learn language-specific gestures by watching others gesture or by learning to speak a particular language? We examined this question by studying the speech and gestures produced by 40 congenitally blind adult native speakers of English and Turkish (n = 20/language), and comparing them with the speech and gestures of 40 sighted adult speakers in each language (20 wearing blindfolds, 20 not wearing blindfolds). We focused on speakers' descriptions of physical motion, which display strong cross-linguistic differences in patterns of speech and gesture use. Congenitally blind speakers of English and Turkish produced speech that resembled the speech produced by sighted speakers of their native language. More important, blind speakers of each language used gestures that resembled the gestures of sighted speakers of that language. Our results suggest that hearing a particular language is sufficient to gesture like a native speaker of that language.