Sex differences in infant vocalization and the origin of language.

Seeking to discern the earliest sex differences in language-related activities, our focus is vocal activity in the first two years of life, following up on recent research that unexpectedly showed boys produced significantly more speech-like vocalizations (protophones) than girls during the first year of life.We now bring a much larger body of data to bear on the comparison of early sex differences in vocalization, data based on automated analysis of all-day recordings of infants in their homes. The new evidence, like that of the prior study, also suggests boys produce more protophones than girls in the first year and offers additional basis for informed speculation about biological reasons for these differences.

Language Experience in the Second Year of Life and Language Outcomes in Late Childhood.

Objectives: Quantity of talk and interaction in the home during early childhood is correlated with socioeconomic status (SES) and can be used to predict early language and cognitive outcomes. We tested the effectiveness of automated early language environment estimates for children 2 to 36 months old to predict cognitive and language skills 10 years later and examined effects for specific developmental age periods.

Methods: Daylong audio recordings for 146 infants and toddlers were completed monthly for 6 months, and the total number of daily adult words and adult-child conversational turnswere automatically estimated with Language Environment Analysis software.

Automated Assessment of Child Vocalization Development Using LENA.

Purpose: To produce a novel, efficient measure of children's expressive vocal development on the basis of automatic vocalization assessment (AVA), child vocalizations were automatically identified and extracted from audio recordings using Language Environment Analysis (LENA) System technology.

Method: Assessment was based on full-day audio recordings collected in a child's unrestricted, natural language environment. AVA estimates were derived using automatic speech recognition modeling techniques to categorize and quantify the sounds in child vocalizations (e.

Mapping the Early Language Environment Using All-Day Recordings and Automated Analysis.

Purpose: This research provided a first-generation standardization of automated language environment estimates, validated these estimates against standard language assessments, and extended on previous research reporting language behavior differences across socioeconomic groups.

Method: Typically developing children between 2 to 48 months of age completed monthly, daylong recordings in their natural language environments over a span of approximately 6-38 months. The resulting data set contained 3,213 12-hr recordings automatically analyzed by using the Language Environment Analysis (LENA) System to generate estimates of (a) the number of adult words in the child's environment, (b) the amount of caregiver-child interaction, and (c) the frequency of child vocal output.

Conceptualizing a Public Health Prevention Intervention for Bridging the 30 Million Word Gap.

Early childhood experience is a social determinant of children's health and well-being. The well-being of young children is founded on their relationships and interactions with parents and family members in the home, caregivers, and teachers in early education, and friends and families in the greater community. Unfortunately, the early language experience of infants and toddlers from low-income families is typically vastly different than children from middle- and higher-income families.

The stability and validity of automated vocal analysis in preverbal preschoolers with autism spectrum disorder.

Theory and research suggest that vocal development predicts "useful speech" in preschoolers with autism spectrum disorder (ASD), but conventional methods for measurement of vocal development are costly and time consuming. This longitudinal correlational study examines the reliability and validity of several automated indices of vocalization development relative to an index derived from human coded, conventional communication samples in a sample of preverbal preschoolers with ASD. Automated indices of vocal development were derived using software that is presently "in development" and/or only available for research purposes and using commercially available Language ENvironment Analysis (LENA) software.

Evaluating language environment analysis system performance for Chinese: a pilot study in Shanghai.

Purpose: The purpose of this study was to evaluate performance of the Language Environment Analysis (LENA) automated language-analysis system for the Chinese Shanghai dialect and Mandarin (SDM) languages.

Method: Volunteer parents of 22 children aged 3-23 months were recruited in Shanghai. Families provided daylong in-home audio recordings using LENA.

Automated Vocal Analysis of Children With Hearing Loss and Their Typical and Atypical Peers.

Objectives: This study investigated automatic assessment of vocal development in children with hearing loss compared with children who are typically developing, have language delays, and have autism spectrum disorder. Statistical models are examined for performance in a classification model and to predict age within the four groups of children.

Design: The vocal analysis system analyzed 1913 whole-day, naturalistic acoustic recordings from 273 toddlers and preschoolers comprising children who were typically developing, hard of hearing, language delayed, or autistic.

A social feedback loop for speech development and its reduction in autism.

We analyzed the microstructure of child-adult interaction during naturalistic, daylong, automatically labeled audio recordings (13,836 hr total) of children (8- to 48-month-olds) with and without autism. We found that an adult was more likely to respond when the child's vocalization was speech related rather than not speech related. In turn, a child's vocalization was more likely to be speech related if the child's previous speech-related vocalization had received an immediate adult response rather than no response.

Automated analysis of child phonetic production using naturalistic recordings.

Purpose: Conventional resource-intensive methods for child phonetic development studies are often impractical for sampling and analyzing child vocalizations in sufficient quantity. The purpose of this study was to provide new information on early language development by an automated analysis of child phonetic production using naturalistic recordings. The new approach was evaluated relative to conventional manual transcription methods.

Vocal interaction between children with Down syndrome and their parents.

Purpose: The purpose of this study was to describe differences in parent input and child vocal behaviors of children with Down syndrome (DS) compared with typically developing (TD) children. The goals were to describe the language learning environments at distinctly different ages in early childhood.

Method: Nine children with DS and 9 age-matched TD children participated; 4 children in each group were ages 9-11 months, and 5 were between 25 and 54 months.

Stability and validity of an automated measure of vocal development from day-long samples in children with and without autism spectrum disorder.

Individual difference measures of vocal development may eventually aid our understanding of the variability in spoken language acquisition in children with autism spectrum disorder (ASD). Large samples of child vocalizations may be needed to maximize the stability of vocal development estimates. Day-long vocal samples can now be automatically analyzed based on acoustic characteristics of speech likeness identified in theoretically driven and empirically cross-validated quantitative models of typical vocal development.

Objective child behavior measurement with naturalistic daylong audio recording and its application to autism identification.

Child behavior in the natural environment is a subject that is relevant for many areas of social science and bio-behavioral research. However, its measurement is currently based mainly on subjective approaches such as parent questionnaires or clinical observation. This study demonstrates an objective and unobtrusive child vocal behavior measurement and monitoring approach using daylong audio recordings of children in the natural home environment.

Child vocalization composition as discriminant information for automatic autism detection.

Early identification is crucial for young children with autism to access early intervention. The existing screens require either a parent-report questionnaire and/or direct observation by a trained practitioner. Although an automatic tool would benefit parents, clinicians and children, there is no automatic screening tool in clinical use.

What automated vocal analysis reveals about the vocal production and language learning environment of young children with autism.

The study compared the vocal production and language learning environments of 26 young children with autism spectrum disorder (ASD) to 78 typically developing children using measures derived from automated vocal analysis. A digital language processor and audio-processing algorithms measured the amount of adult words to children and the amount of vocalizations they produced during 12-h recording periods in their natural environments. The results indicated significant differences between typically developing children and children with ASD in the characteristics of conversations, the number of conversational turns, and in child vocalizations that correlated with parent measures of various child characteristics.

Teaching by listening: the importance of adult-child conversations to language development.

Objective: To test the independent association of adult language input, television viewing, and adult-child conversations on language acquisition among infants and toddlers.

Methods: Two hundred seventy-five families of children aged 2 to 48 months who were representative of the US census were enrolled in a cross-sectional study of the home language environment and child language development (phase 1). Of these, a representative sample of 71 families continued for a longitudinal assessment over 18 months (phase 2).

Audible television and decreased adult words, infant vocalizations, and conversational turns: a population-based study.

Objective: To test the hypothesis that audible television is associated with decreased parent and child interactions.

Design: Prospective, population-based observational study.

Setting: Community.