Beyond Mean Length of Utterance: Novel Measures for Characterizing the Spoken Language of Autistic Children.

Language development in children with autism is influenced by proximal (e.g., parent language input) and distal (e.g., socioeconomic status) environmental constructs. Studies have found that "rich and responsive" parent language input supports autistic children's language development, and recent work has reported positive associations between measures of socioeconomic status (SES) and child language skills. However, little is known about how these proximal and distal environmental constructs interact to shape language development in autism. In a sample of 74 autistic school-aged children, the present study investigated the associations among measures of SES, the quantity and quality of language produced by parents and children during home-based dyadic parent-child interactions, and children's expressive and receptive language skills. Results showed that annual household income was positively associated with parent number of total words (NTW), parent number of different words (NDW), and parent mean length of utterance (MLU), while neither parent education level nor annual household income were significantly associated with measures of child language skills. Parent MLU was positively associated with child MLU and child expressive language skills. Findings suggest that annual household income may influence both the quantity and quality of parent language input, and that parent MLU, a qualitative measure of parent language input, may play a particularly important role in shaping autistic children's expressive language development. Future research should study longitudinal associations among SES, parent language input, and child language skills, as identifying environmental predictors of language skills in autism may facilitate the creation of more effective interventions that support language development.

Conversational latency entails the temporal feature of turn-taking, which is understudied in autistic children. The current study investigated the influences of child-based and parental factors on conversational latency in autistic children with heterogeneous spoken language abilities. Participants were 46 autistic children aged 4-7 years. We remotely collected 15-min naturalistic language samples in the context of parent-child interactions to characterize both child and parent conversational latency. Conversational latency was operationally defined as the time it took for one individual to respond to their conversational partner using spoken language. Naturalistic language samples were transcribed following the Systematic Analysis for Language Transcripts convention to characterize autistic children's spoken language and parental spoken language input. Autistic children's spoken language was measured using number of different words (NDW). The quality and quantity of parental spoken language input was assessed using NDW, mean length of utterance in morphemes (MLUm), and frequency of words per minute (WPM). Additional child-based factors, including receptive language and socialization skills, were evaluated using the Vineland Adaptive Behavior Scales. Spearman correlation and regression analyses were conducted to investigate the relationships between those child-based and parental factors and child conversational latency. Older autistic children showed longer conversation latencies. Longer parent conversational latency was associated with longer child conversational latency after controlling for age. Greater parental WPM was associated with shorter child conversational latency after controlling for age. Child conversational latency was not associated with their spoken language, receptive language, or socialization skills. Child conversational latency was not associated with parental NDW and MLUm. Our findings highlight the interaction loop between autistic children and their parents in everyday interactions. Parents adjusted their timing and quantity of spoken language input to ensure smooth conversational turn-taking when interacting with their autistic children.

A meta-analysis of the association between vocalizations and expressive language in children with autism spectrum disorder

The frequency and types of questions that four hearing mothers used with their 3- and 4-year-old deaf daughters was examined. Relationships between frequency and type of question and child mean length of utterance (MLU) measurements were also explored. Results indicated that the mothers used fewer questions than hearing mothers of hearing children but that the types of questions used were similar. Three mothers used text-related indirect commands, a question type not examined frequently in previous research. Child MLU measurements appeared to influence the amount and types of questions mothers used, although MLU, as measured in this study, may not have been a valid descriptor of the children's expressive language. Implications for the quality of language during joint book reading with young deaf children are discussed.

We examined the associations of breastfeeding initiation and duration with language and motor skill development in a nationally representative sample of US children aged 10 to 71 months. Using cross-sectional data on 22399 children from the 2003 National Survey of Children's Health, we examined relationships between breastfeeding practices and children's language and motor skills development. Outcomes were based on each mother's response to questions regarding her level of concern (a lot, a little, not at all) about her child's development of expressive language, receptive language, fine motor skills, and gross motor skills. Breastfeeding data were based on mothers' recall. Methods of variance estimation were applied and multivariate polynomial regression modeling was done to estimate the effects of breastfeeding initiation and duration on children's development after adjustment for confounders. Mean age of the sample was 2.79 years; 67% were non-Hispanic white, 16% were Hispanic, and 9% were non-Hispanic black. Approximately 17% of mothers reported concerns about their child's expressive language development; approximately 10% had receptive language concerns; approximately 6% had concerns about fine motor skills; and 5% reported general motor skills concerns. Multivariate analysis revealed that mothers who initiated breastfeeding were less likely than mothers of never-breastfed children to be concerned a lot about their child's expressive and receptive language development and fine and general motor skills. Mothers of children breastfed 3 to 5.9 months were less likely than mothers of never-breastfed children to be concerned a lot about their child's expressive and receptive language and fine and general motor skills. As with all cross-sectional data, results should be interpreted with caution. Our findings suggest breastfeeding may protect against delays in young children's language and motor skill development. Fewer concerns about language and motor skill development were evident for children breastfed >or=3 months, and concerns generally decreased as breastfeeding continued >or=9 months.

In spite of the close relationship between gestures and expressive language, little research has examined the roles of the parents' and children's gestures in the development of expressive language abilities in autistic children. Previous findings are also inconclusive. In the present study, we coded the gestures produced by the parents and their autistic children in parent-child interactions and compared the influence of their gestures on the children's expressive language abilities (N = 35; M = 4;10). Autistic children's deictic gestures positively predicted their Mean Length Utterance (MLU), word types, and word tokens whereas parents' deictic gesture inputs negatively predicted MLU and word types. The findings shed light on the importance of the gestures made by autistic children, which may trigger parents' gesture-to-word translation.

Purpose Several studies have reported that "useful speech" at 5 years of age predicts outcomes in individuals with autism spectrum disorder (ASD), but this skill has been vaguely defined. This study investigates which specific aspects of expressive language in children with ASD best predict adult language and communication outcomes. Method Language samples from 29 children (ages 47-72 months) enrolled in a longitudinal project (e.g., Lord et al., 2006) were transcribed and coded for spoken language features. Hierarchical linear regression was used to compare the following childhood variables as predictors of adult language and communication outcomes: noun diversity, verb diversity, mean length of utterance, and proportion of utterances that were socially motivated. Results Childhood verb diversity was a value-added predictor of all four adult outcome measures (i.e., verbal IQ, Autism Diagnostic Observation Schedule Communication + Social Interaction Algorithm totals, Peabody Picture Vocabulary Test scores, and Vineland Adaptive Behavior Scales Communication Domain scores), while noun diversity and proportion of utterances that were socially motivated were not value-added predictors of any adult outcome measures. In a second set of regression analyses, mean length of utterance was substituted for verb diversity and was a value-added predictor of two out of four adult outcome measures (i.e., verbal IQ and Vineland Adaptive Behavior Scales Communication Domain scores). The pattern of findings for the other predictors remained the same as in the previous analyses. Conclusion These results have implications for our understanding of early language in ASD and for clinical decision making in early childhood.

The length of longest utterances (LLU) may offer a useful view of the upper boundaries of a child's early expressive grammar. In this study, the properties of four measures of LLU were examined in terms of their relationships to mean length of utterance (MLU) and to language sample size over the course of early development. The four measures of LLU were (1) mean length of the longest three utterances (LLU-3), (2) mean length of the longest 10% of utterances (LLU-10%), (3) MLUs over the median utterance length (LLU-M), and (4) MLUs longer than one morpheme (LLU > 1). Language samples of various sizes were created by randomly selecting subsets of 50, 100, 200, and 300 utterances from Brown's samples of Adam, Eve, and Sarah. The four calculation methods were compared in each of the sample sizes, over the course of development for each child. The results indicated that LLU-M and LLU > 1 were both close to MLU, although age differences were noted. Increases in LLU tended to outpace MLU over development in three of the four calculation methods. LLU was positively related to language sample size for one of the calculation methods, LLU-3. Overall, LLU was found to be a fairly close parallel of MLU and a good predictor of future MLU values. It was concluded that three basic properties of LLU should be taken into consideration: (1) calculation method affects LLU outcome, (2) LLU gradually increases relative to MLU throughout early development, and (3) LLU is affected by interaction of language sample size with calculation method.

Language impairment is one of the early signs of Autism Spectrum Disorder (ASD) that alerts parents to take their children for early diagnosis and intervention. Little is known about how children's autism traits, IQ, initial language abilities and parental inputs influence their language abilities. In addition, only a few studies have compared the relative influence of these factors. The present study addressed these issues by examining the structural language in parent-child spontaneous interactions. Forty-two Cantonese (Chinese)-speaking autistic children aged four to eight were recruited. Their expressive language skills grew rapidly more than 9 months, but their development trajectories varied. Initial expressive language ability is the only significant predictor of child language outcomes and language growth trajectories. In contrast, nonverbal cognition, autism traits, and parents' input do not affect language outcomes in children with ASD. Therefore, early language intervention is crucial for autistic children at all severity and IQ levels.

The task of developing prognoses for late-talking children has long been a challenge for speech-language pathologists, developmental psychologists, and pediatricians. Improved predictors would help to assess long-term risk and determine appropriate intervention services. The present study evaluated children’s length of longest utterances (LLU) as a predictor of mean length of utterance (MLU) one year later. Relationships between LLU at 30 months, MLU at 30 months and MLU at 42 months were examined in 43 late talkers (LT) and 33 age-matched children whose language was typically developing (TD). LLU was a significant predictor of MLU at 42 months with particularly strong correlations within the LT group. Similar results were obtained when controlling for language sample size, which was positively related to LLU. For the LT group, a regression model combining 30-month LLU and MLU was better at predicting 42-month MLU than 30-month MLU alone. The results are discussed in terms of frequency distributions of utterance lengths within language samples.

Mean length of utterance (MLU) is one of the most widely reported measures of syntactic development in the developmental literature, but its responsiveness in young school-age children's language has been questioned, and it has been shown to correlate with nonsyntactic measures. This study tested the extent to which MLU shows measurement properties of responsiveness and construct validity when applied to language elicited from elementary school children. Thirty-two typically developing children in two age groups (5 and 8 years) provided four short language samples each. Language samples were elicited in a question-answer context and a narrative context. MLU was calculated with both morpheme and word counts. Other established measures of syntactic complexity (clausal density [CD], developmental level [D-Level], mean length of clause [MLC]) and lexical diversity (lexical density, moving-average type-token ratio, number of different words) were also calculated. Linear mixed-effects analyses revealed that MLU varied systematically with discourse context and children's age group. The syntactic measures, CD and MLC, were found to vary systematically with MLU. None of the lexical diversity measures varied systematically with MLU. Results suggest that MLU is a responsive and valid measure of children's syntactic development across age and discourse context during the early school-age years.

We examined the language input of parents of infants at high and low familial risk for autism spectrum disorder (ASD) and investigated reciprocal associations between parent input and child language skills in the first 2 years of life. Parent-infant dyads (high-risk: n = 53; low-risk: n = 33), 19 of whom included an infant later diagnosed with ASD, were videotaped during free play interactions at 12, 18, and 24 months. Measures of parent input were derived from parent-child interactions. Children's language skills were assessed using the Mullen Scales of Early Learning at 12, 18, and 24 months. Results suggested that (a) parents of high- and low-risk infants produced similar word tokens, word types, and proportions of contingent verbal responses, but parents of high-risk infants used shorter mean length of utterances (MLU) than parents of low-risk infants at 18 and 24 months; (b) parents' MLU at 18 months was positively associated with their infants' language at the subsequent visit after 6 months, regardless of group; and (c) infants' language at 18 months was positively associated with parents' MLU at the subsequent visit after 6 months in the high-risk group only. These findings contribute to our understanding of the mechanisms underlying early language learning of high-risk infants who have an increased risk for language delays and deficits. Autism Res 2020, 13: 1168-1183. © 2020 International Society for Autism Research, Wiley Periodicals, Inc. LAY SUMMARY: Parents provide an important source of language input to their children. In this study, we looked at parent input to infants at high- and low-risk for autism spectrum disorder and relations between parent input and child language in the first 2 years of life. We found that parents of high- and low-risk infants provided similar quantity and quality of input, except shorter average length of utterances at 18 and 24 months in the high-risk group. Also, there were bidirectional relations between parent input and child language at 18 and 24 months in high-risk pairs, suggesting that parents and children collectively shape the early language environment.

Fine motor skill is associated with expressive language outcomes in infants who have an autistic sibling and in young autistic children. Fewer studies have focused on school-aged children even though around 80% have motor impairments and 30% remain minimally verbal (MV) into their school years. Moreover, expressive language is not a unitary construct, but it is made up of components such as speech production, structural language, and social-pragmatic language use. We used natural language sampling to investigate the relationship between fine motor and speech intelligibility, mean length of utterance and conversational turns in MV and verbal autistic children between the ages of 4 and 7 while controlling for age and adaptive behavior. Fine motor skill predicted speech production, measured by percent intelligible utterances. Fine motor skill and adaptive behavior predicted structural language, measured by mean length of utterance in morphemes. Adaptive behavior, but not fine motor skill, predicted social-pragmatic language use measured by number of conversational turns. Simple linear regressions by group corrected for multiple comparisons showed that fine motor skill predicted intelligibility for MV but not verbal children. Fine motor skill and adaptive behavior predicted mean length of utterance for both MV and verbal children. These findings suggest that future studies should explore whether MV children may benefit from interventions targeting fine motor along with speech and language into their school years.

This study examined the relation between mothers' sensitive responsiveness to their children and the children's expressive language skills during early childhood. Reciprocal effects were tested with dyads of mothers and their children participating in the National Institute of Health and Human Development Study of Early Child Care and Youth Development. Sensitive maternal interactions positively affected children's later expressive language in the second and third years of life. Although maternal sensitivity predicted later language skills in children, children's language did not affect later maternal sensitivity as indicated in a structural equation model. These results do not support the 1975 transactional model of child development of Sameroff and Chandler. A consistent pattern of sensitivity throughout infancy and early childhood indicates the importance of fostering maternal sensitivity in infancy for prevention or remediation of expressive language problems in young children.

Mean length of utterance (MLU) is a frequently used measure of the expressive language of young children. The suggested conventional, contemporary, clinical practice is to calculate it from a language sample of a minimum of 50 to100 contiguous intelligible utterances. This practice places considerable strain on professionals working with young children with language disorders, for it is often impractical to devote the time needed to collect, transcribe, and analyse the recommended number of utterances. This research investigated the consistency of MLU calculated across language samples of different sizes for the same children. Transcripts of expressive language samples of research participants with developmental language impairment were analysed, with MLU being calculated on samples of varying sizes. The language samples ranged from 10 to 150 utterances. Measures of statistical differences and consistency of MLU across the various language samples were examined. Results demonstrate that, on the whole, one can reliably and efficiently determine MLU on much smaller language samples than that typically recommended, although, not surprisingly, there may be notable individual differences attesting to the vicissitudes of MLU.