Making Object Shape Explicit for Toddlers With Late Language Emergence

Late Talkers can generalise trained labels by object shape similarities, but not unfamiliar labels

Late talkers (LTs) exhibit delayed vocabulary development, which might stem from a lack of a typical word learning strategy to generalise object labels by shape, called the 'shape bias'. We investigated whether LTs can acquire a shape bias and whether this accelerates vocabulary learning. Fourteen LTs were randomly allocated to either a shape training group (Mage = 2.76 years, 6 males), which was taught that objects similar in shape have the same name, or a control group (Mage = 2.61 years, 4 males), which was taught real words without any focus on object shape. After seven training sessions, children in the shape training group generalised trained labels by shape (d = 1.28), but not unfamiliar labels. Children in the control group extended all labels randomly. Training did not affect expressive vocabulary.

Object Shape and Depth of Word Representations in Preschoolers

This study examined the effect of a shape cue (i.e., co-speech gesture) on word depth. We taught 23 preschoolers (M = 3;5 years, SD = 5.82) novel objects with either shape (SHP) or indicator (IND) gestures. SHP gestures mimicked object form, but IND gestures were not semantically related to the object (e.g., an upward-facing palm, extended toward the object). Each object had a unique IND or SHP gesture. Outcome measures reflected richer semantic and phonological learning in the SHP than in the IND condition. In the SHP condition, preschoolers (a) expressed more semantic knowledge, (b) said more sounds in names, and (c) generalized more names to untaught objects. There were also fewer disruptions to prime picture names in the SHP condition; we discuss the benefit of a co-speech shape gesture to capitalize on well-established statistical word learning patterns.

Phonological and Articulatory Deficits in the Production of Novel Signs in Children With Developmental Language Disorder

PURPOSE

Sign language, like spoken language, incorporates phonological and articulatory (or motor) processing components. Thus, the learning of novel signs, like novel spoken word forms, may be problematic for children with developmental language disorder (DLD). In the present work, we hypothesize that phonological and articulatory deficits in novel sign repetition and learning would differentiate preschool-age children with DLD from their typical peers.

METHOD

Children with DLD (n = 34; aged 4-5 years) and their age-matched typical peers (n = 21) participated. Children were exposed to four novel signs, all iconic, but only two linked to a visual referent. Children imitatively produced these novel signs multiple times. We obtained measures of phonological accuracy and articulatory motion stability as well as of learning of the associated visual referent.

RESULTS

Children with DLD showed an increased number of phonological feature (i.e., handshape, path, and orientation of the hands) errors when compared with their typical peers. While articulatory variability did not overall differentiate children with DLD from typical peers, children with DLD showed instability in one novel sign that obligated bimanual oppositional movement. Semantic aspects of novel sign learning were unaffected in children with DLD.

CONCLUSIONS

Deficits that have been documented in phonological organization of spoken words in children with DLD are also evident in the manual domain. Analyses of hand motion variability suggest that children with DLD do not show a generalized motor deficit, but one that is restricted to the implementation of coordinated and sequential hand motion.

Gesture Development in Chinese-Speaking Preschool Children With Autism and the Roles of Parental Input and Child-Based Factors

PURPOSE

Children with autism are found to have delayed and heterogeneous gesture abilities. It is important to understand the growth of gesture abilities and the underlying factors affecting its growth. Addressing these issues can help to design effective intervention programs.

METHOD

Thirty-five Chinese-speaking preschoolers with autism spectrum disorder (M _age = 4.89 years, SD = 0.91; four girls) participated in four play sessions with their parents over 9 months. Their child-based factors including autism severity, intellectual functioning, and expressive language abilities were assessed. The gestures (deictic, iconic, and conventional) of the children and their parents were coded. Growth curve analyses were conducted to examine individual growth trajectories and the roles of child-based factors and parental input in shaping the children's gesture development.

RESULTS

Child-based factors and parental input predicted gesture development differently. Parents' gestures positively predicted their children's gestures of the same type. Autism severity negatively predicted iconic and conventional gestures. Overall growth was found in deictic rather than iconic and conventional gestures. Subgroup variation was also found. Specifically, children with better expressive language ability showed a decrease in deictic gestures. An increase in iconic and conventional gestures was found in children with more severe autism and those with poorer expressive language ability and intellectual functioning, respectively.

CONCLUSIONS

Different types of gestures may have different growth trajectories and be predicted by different child-based factors. Particular attention should be given to children who never produced iconic gestures, which is more challenging and may not develop over a short period, and hence require direct instruction.

Can gesture input support toddlers' fast mapping?

Forty-eight toddlers participated in a word-learning task to assess gesture input on mapping nonce words to unfamiliar objects. Receptive fast mapping and expressive naming for target object-word pairs were tested in three conditions - with a point, with a shape gesture, and in a no-gesture, word-only condition. No statistically significant effect of gesture for receptive fast-mapping was found but age was a factor. Two year olds outperformed one year olds for both measures. Only one girl in the one-year-old group correctly named any items. There was a significant interaction between gesture and gender for expressive naming. Two-year-old girls were six times more likely than two-year-old boys to correctly name items given point and shape gestures; whereas, boys named more items taught with the word only than with a point or shape gesture. The role of gesture input remains unclear, particularly for children under two years and for toddler boys.

Phonological characteristics of novel gesture production in children with developmental language disorder: Longitudinal findings

Children with developmental language disorder (DLD; aka specific language impairment) are characterized based on deficits in language, especially morphosyntax, in the absence of other explanatory conditions. However, deficits in speech production, as well as fine and gross motor skill, have also been observed, implicating both the linguistic and motor systems. Situated at the intersection of these domains, and providing insight into both, is manual gesture. In the current work, we asked whether children with DLD showed phonological deficits in the production of novel gestures and whether gesture production at 4 years of age is related to language and motor outcomes two years later. Twenty-eight children (14 with DLD) participated in a two-year longitudinal novel gesture production study. At the first and final time points, language and fine motor skills were measured and gestures were analyzed for phonological feature accuracy, including handshape, path, and orientation. Results indicated that, while early deficits in phonological accuracy did not persist for children with DLD, all children struggled with orientation while handshape was the most accurate. Early handshape and orientation accuracy were also predictive of later language skill, but only for the children with DLD. Theoretical and clinical implications of these findings are discussed.

Repetition Versus Variability in Verb Learning: Sometimes Less Is More

Purpose This study examined whether 2-year-olds are better able to acquire novel verb meanings when they appear in varying linguistic contexts, including both content nouns and pronouns, as compared to when the contexts are consistent, including only content nouns. Additionally, differences between typically developing toddlers and late talkers were explored. Method Forty-seven English-acquiring 2-year-olds (n = 14 late talkers, n = 33 typically developing) saw scenes of actors manipulating objects. These actions were labeled with novel verbs. In the varied condition, children heard sentences containing both content nouns and pronouns (e.g., "The girl is ziffing the truck. She is ziffing it!"). In the consistent condition, children heard the verb an equal number of times, but only with content nouns (e.g., "The girl is ziffing the truck. The girl is ziffing the truck!"). At test, children were shown two new scenes and were asked to find the novel verb's referent. Children's eye gaze was analyzed as a measure of learning. Results Mixed-effects regression analyses revealed that children looked more toward the correct scene in the consistent condition than the varied condition. This difference was more pronounced for late talkers than for typically developing children. Conclusion To acquire an initial representation of a new verb's meaning, children, particularly late talkers, benefit more from hearing the verb in consistent linguistic contexts than in varying contexts.