Input and Processing Factors Affecting Infants’ Vocabulary Size at 19 and 25 Months

This study examined the relative contributions of three factors to individual differences in vocabulary development: the acoustic quality of mothers’ speech, the quantity of mothers’ speech, and infants’ ability to recognize words. To examine the quality and quantity of mothers’ speech, recordings were collected from 48 mothers when their infants were 17 months old. Infants’ ability to recognize words was gauged by their performance in a perception experiment at 19 months. We examined the relationship between these measures and infants’ vocabulary size at 19 and 25 months. The quantity of mothers’ speech accounted for the greatest amount of variance in infants’ vocabulary size at 19 months; infants’ ability to recognize words followed next. At 25 months, when mothers’ speech alone is presumably no longer the primary input for infants, infants’ ability to recognize words at 19 months was a better predictor of vocabulary size. The acoustic quality of mothers’ speech was not correlated with infants’ vocabulary size at either age. The findings highlight the importance of considering multiple factors that contribute to early word learning, providing a better understanding of the mechanisms underlying the facilitation process.

[1]  Michelle L. McGillion,et al.  What Paves the Way to Conventional Language? The Predictive Value of Babble, Pointing, and Socioeconomic Status. , 2017, Child development.

[2]  J. Singer,et al.  Maternal correlates of growth in toddler vocabulary production in low-income families. , 2005, Child development.

[3]  Katharine Graf Estes,et al.  Mapping sound to meaning: connections between learning about sounds and learning about words. , 2006, Advances in child development and behavior.

[4]  Matthew D. Parker,et al.  A comparative study between mean length of utterance in morphemes (MLUm) and mean length of utterance in words (MLUw) , 2005 .

[5]  M. Weinraub,et al.  Maternal speech: strategy or response? , 1983, Journal of Child Language.

[6]  Kathy Hirsh-Pasek,et al.  Word Learning in Infant- and Adult-Directed Speech , 2011, Language learning and development : the official journal of the Society for Language Development.

[7]  M. Rowe,et al.  Input and uptake at 7 months predicts toddler vocabulary: the role of child-directed speech and infant processing skills in language development , 2015, Journal of Child Language.

[8]  Magnus Lindgren,et al.  Productive Vocabulary Size Predicts Event-related Potential Correlates of Fast Mapping in 20-Month-Olds , 2008, Journal of Cognitive Neuroscience.

[9]  R. DePaolis,et al.  The Relationship Between Infants’ Production Experience and Their Processing of Speech , 2014 .

[10]  Amy Perfors,et al.  Picking up speed in understanding: Speech processing efficiency and vocabulary growth across the 2nd year. , 2006, Developmental psychology.

[11]  J. Reznick,et al.  Early lexical acquisition: rate, content, and the vocabulary spurt , 1990, Journal of Child Language.

[12]  L. Fenson,et al.  Lexical development norms for young children , 1996 .

[13]  T. Zamuner.  Phonotactic probabilities at the onset of language development: speech production and word position. , 2009, Journal of speech, language, and hearing research : JSLHR.

[14]  J. Werker,et al.  Early word-object associations and later language development , 2007 .

[15]  S. Suter.  Meaningful differences in the everyday experience of young American children , 2005, European Journal of Pediatrics.

[16]  Maria Uther,et al.  Do you speak E-NG-L-I-SH? A comparison of foreigner- and infant-directed speech , 2007, Speech Commun..

[17]  P. Kuhl,et al.  Cross-language analysis of phonetic units in language addressed to infants. , 1997, Science.

[18]  Jane L. Abraham,et al.  The development of infants' preference for motherese , 1997 .

[19]  R. Newman,et al.  Infant-directed speech (IDS) vowel clarity and child language outcomes* , 2016, Journal of Child Language.

[20]  D. Kimbrough Oller,et al.  Language Experience in the Second Year of Life and Language Outcomes in Late Childhood , 2018, Pediatrics.

[21]  P. Kuhl,et al.  Speech perception in infancy predicts language development in the second year of life: a longitudinal study. , 2004, Child development.

[22]  Peter Hagoort,et al.  Predicting individual variation in language from infant speech perception measures. , 2014, Child development.

[23]  P. Kuhl,et al.  Early Speech Perception and Later Language Development: Implications for the "Critical Period" , 2005 .

[24]  Laurence B. Leonard,et al.  Individual differences in early child phonology , 1980, Applied Psycholinguistics.

[25]  David M. Sobel,et al.  Attention to the mouth and gaze following in infancy predict language development. , 2015, Journal of child language.

[26]  E. Bates,et al.  INDIVIDUAL DIFFERENCES AND THEIR IMPLICATIONS FOR THEORIES OF LANGUAGE DEVELOPMENT , 1995 .

[27]  Patricia K. Kuhl,et al.  Fast Track , 2020, Electric and Hybrid Vehicle Technology International.

[28]  R. Brown,et al.  A First Language , 1973 .

[29]  Jonas Beskow,et al.  Wavesurfer - an open source speech tool , 2000, INTERSPEECH.

[30]  Letitia R. Naigles,et al.  How children use input to acquire a lexicon. , 2002, Child development.

[31]  Anne Fernald,et al.  Does input influence uptake? Links between maternal talk, processing speed and vocabulary size in Spanish-learning children. , 2008, Developmental science.

[32]  Mitsuhiko Ota,et al.  Reduplication facilitates early word segmentation* , 2015, Journal of Child Language.

[33]  S. Stokes,et al.  Factors that influence vocabulary development in two-year-old children. , 2009, Journal of child psychology and psychiatry, and allied disciplines.

[34]  Stephanie F Stokes,et al.  Neighborhood density and word frequency predict vocabulary size in toddlers. , 2010, Journal of speech, language, and hearing research : JSLHR.

[35]  A. Fernald,et al.  A cross-language study of prosodic modifications in mothers' and fathers' speech to preverbal infants , 1989, Journal of Child Language.

[36]  P. Jusczyk,et al.  Infants' early ability to segment the conversational speech signal predicts later language development: a retrospective analysis. , 2006, Developmental psychology.

[37]  V. Marchman,et al.  Speed of word recognition and vocabulary knowledge in infancy predict cognitive and language outcomes in later childhood. , 2008, Developmental science.

[38]  M. Vihman,et al.  Individual differences in phonological development: ages one and three years. , 1987, Journal of speech and hearing research.

[39]  Katherine Demuth,et al.  Effects of the acoustic properties of infant-directed speech on infant word recognition. , 2010, The Journal of the Acoustical Society of America.

[40]  Alejandrina Cristià,et al.  Fine-grained variation in caregivers' /s/ predicts their infants' /s/ category. , 2011, The Journal of the Acoustical Society of America.

[41]  Björn Lindblom,et al.  Phonetic variability and Baby Talk , 2001 .

[42]  B. MacWhinney.  The CHILDES project: tools for analyzing talk , 1992 .

[43]  Anne Fernald,et al.  Talking to Children Matters , 2013, Psychological science.

[44]  Erik D. Thiessen,et al.  Infant-Directed Speech Facilitates Word Segmentation. , 2005, Infancy : the official journal of the International Society on Infant Studies.

[45]  Alison J. Bahnsen,et al.  Predictors of morphosyntactic growth in typically developing toddlers: contributions of parent input and child sex. , 2011, Journal of speech, language, and hearing research : JSLHR.