I am interested in how the speech that infants and young children hear affects early language acquisition. My current research focuses on complementary questions of the nature of such speech, particularly with regard to properties that may cue aspects of language structure, and the nature of early perceptual capacities for extracting and representing the structural information that is cued.

I am interested in how the speech that infants and young children hear affects early language acquisition. My current research focuses on complementary questions of the nature of such speech, particularly with regard to properties that may cue aspects of language structure, and the nature of early perceptual capacities for extracting and representing the structural information that is cued. This work bears on the theoretical characterization of the initial state with regard to language learning: To the extent that input speech is rich in cues to structure that infants can represent appropriately, the need for imputing abstract grammatical knowledge to infants (as many recent theories have done) will be reduced.

Recent work in my laboratory on the properties of speech to infants shows that repeated tokens of words tend to be less phonetically variable (though more prosodically variable) in speech to infants than in speech to adults. This may aid infants in recognizing different tokens as exemplars of the same word and may assist in the establishment of the mental lexicon. Different grammatical categories of words possess varying constellations of acoustic, phonetic, and phonological properties; hence, these properties of speech may provide a basis for infants to begin to assign words to appropriate categories.

For her doctoral dissertation at Brown, Rushen Shi (now assistant professor at the University of British Columbia) showed that sets of cues in typologically distinctive languages are sufficient to allow untutored learners to categorize lexical and grammatical words accurately. At present, Heather Bortfeld, a National Research Service Award (NRSA) post-doctoral fellow, is investigating the prosodic and phonological correlates of the given/new distinction in English and Spanish infant-directed speech, and Leher Singh, a first-year graduate student, is analyzing the differences between "happy talk" and "baby talk" as the initial step toward studying whether infants' listening preferences are determined by speech affect or register. As a follow-up to her dissertation, Rushen Shi has been studying whether very young infants can categorically discriminate sets of lexical and grammatical words - categories that appear to be based on correlated acoustic/phonological properties. Shi, Werker, & Morgan (in submission) show that both 6-month-olds and 3-day-olds(!) succeed in this discrimination. Three-day-olds recover from habituation symmetrically, but 6-month-olds have already learned that lexical words are more interesting (or perhaps gramatical words aren't worth conciously attending to), so that they display asymmetric recovery from habituation.

Our work on infant speech perception focuses on the problems of how infants solve the word-segmentation problem and the nature of early lexical representations. Although words must initially be no more evident to an infant than they are to an adult listening to a foreign language, well before the end of the first year infants are capable of recognizing at least some words in fluent speech. Our studies show that infants exposed to English begin between 6 and 9 months to deploy a bias for the strong-weak pattern that predominates in the language in grouping syllables and segmenting words. Other studies show that between these two ages infants also begin to utilize language-specific knowledge of phonotactics (concerning permissible sequences of sounds and their relative likelihoods) as an additional means of identifying word boundaries. Ongoing research is examining in detail the development of infants' recognition of familiar words in fluent speech. Some of this research was described in an article in the Brown Alumni Monthly.

RO1 HD32005 National Institutes of Health/National Institute of Child Health and Human Development (NIH/NICHD) "The Development of Spoken Word Recognition" 1996-2009.

RO1 HD068501 National Institutes of Health/National Institute of Child Health and Human Development (NIH/NICHD) "Longitudinal Studies of Spoken Word Recognition and Language Development" 2012-2017.

Thorson, J. C. & Morgan, J. L. (in press). Directing toddler attention: Intonation contours and information structure.  In Proceedings of the 38th Annual Boston University Conference on Language Development. Somerville. MA: Cascadilla Press.

White, K. S., Yee, E., Blumstein, S. E. & Morgan, J. L. (2013) Adults show less sensitivity to phonetic detail in unfamiliar words, too. Journal of Memory and Language, 68, 362-278.

Tenenbaum, E., Shah, R. J., Sobel, D. M., Malle, B. F., & Morgan, J. L. (2013) Increased focus on the mouth among infants in the first year of life: A longitudinal eye-tracking study. Infancy, 18, 534-553.

Feldman, N. H., Myers, E. B., White, K. S., Griffiths, T. L., & Morgan, J. L. (2013). Word-level information influences phonetic learning in adults and infants. Cognition, 127, 427-438.

Feldman, N. H., Griffiths, T. L., Goldwater, S., & Morgan, J. L. (2013) A role for the developing lexicon in phonetic category acquisition. Psychological Review. 120, 751-778.

Conwell, E., & Morgan, J. L. (2012). Is it a noun or is it a verb? Resolving the ambicategoricality problem. Language Learning and Development, 8, 87-112. (Peter Jusczyk Best Paper Award, 2012.

Ren, J., & Morgan, J. L. (2012). The devil in the details: Underspecification in infants’ and adults’ lexical representations. In Proceedings of the 36th Annual Boston University Conference on Language Development (pp. 500-511). Somerville, MA: Cascadilla Press.

Feldman, N. H., Myers, E., White, K. S., Griffiths, T., & Morgan, J. L. (2011). Learners use word-level statistics in phonetic category acquisition. In Proceedings of the 34th Annual Boston University Conference on Language Development. Somerville, MA: Cascadilla Press.

Ostrand, R., Blumstein, S.E., Morgan, J.L. (2011). When hearing lips and seeing voices becomes perceiving speech: Auditory-visual integration in lexical access. In L. Carlson, C.Hölscher, & T. Shipley (Eds.), Proceedings of the 33rd Annual Conference of the Cognitive Science Society (pp. 1376-1381). Austin, TX: Cognitive Science Society.

Ren, J., & Morgan, J. L. (2011). Sub-segmental details in early lexical representation of consonants. In Proceedings of the 17th International Congress of Phonetic Sciences (pp. 1586-1589).

Millotte, S., Morgan, J. L., Margules, S., Bernal, S., Dutat, M., & Christophe, A. (2010). Phrasal prosody constrains word segmentation in French 16-month-olds. Journal of Portugese Linguistics, 9, 67-86

Song, J.-Y., Demuth, K. D., & Morgan, J. L. (2010). Effects of the acoustic properties of infant-directed speech on infant word recognition. Journal of the Acoustical Society of America, 128, 389-400.

Bortfeld, H., & Morgan, J. L. (2010). Is early word-form processing stress-full? How natural variability supports recognition Cognitive Psychology, 60, 241-266.

Feldman, N. H., Griffiths, T. L., & Morgan, J. L. (2009). Learning phonetic categories by learning a lexicon. In N. A. Taatgen & H. van Rijn (Eds.), Proceedings of the 31st Annual Conference of the Cognitive Science Society (pp. 2208-2213). Austin, TX: Cognitive Science Society.

Soderstom, M., Conwell, E., Feldman, N., & Morgan, J. L. (2009). The learner as statistician: three principles of computational success in language acquisition. Developmental Science, 12, 409-411.

Ko, E-S., Soderstrom, M., & Morgan, J. L. (2009) Development of perceptual sensitivity to extrinsic vowel duration in infants learning American English. Journal of the Acoustical Society of America, 126, EL134-139.

Feldman, N. H., Griffiths, T. L., and Morgan, J. L. (2009). The influence of categories on perception: Explaining the perceptual magnet effect as optimal statistical inference. Psychological Review, 116, 752-782.

Molina, G.C., & Morgan, J.L. (2008). The voicing distinction in Spanish word-initial labial stops: A prelude to what Spanish- learning infants can reveal about native- language phonetic category acquisition. Proceedings of the ATINER International Conference on Literature, Language and Linguistics, Athens

White, K. S., & Morgan, J. L. (2008). Subsegmental detail in infants’ early lexical representations. Journal of Memory and Language, 59, 114-132.

Soderstrom, M., Blossom, M., Foygel, I., & Morgan, J. L. (2008) Acoustical cues and grammatical units in speech to two preverbal infants. Journal of Child Language, 35, 869-902.

White, K., Peperkamp, S. & Morgan, J. (2008). Rapid acquisition of phonological alternations by infants. Cognition, 107, 238- 265.

Singh, L., White, K. & Morgan, J. (2008). Building a lexicon in the face of variable input: Effects of pitch and amplitude variation on early word recognition. Language Learning and Development. 4, 157-178.

Soderstrom, M., & Morgan, J. L. (2008) Twenty-two month olds detect verb-noun exchanges in fluent speech: Evidence for category preferences for familiar content words. Proceedings of the 32nd Annual Boston University Conference on Language Development. Somerville, MA: Cascadilla Press.

Conwell, E., & Morgan, J. L. (2007). Resolving grammatical category ambiguity in acquisition. In H. Caunt-Nulton, S. Kulatilake, & I. Woo (eds.) Proceedings of the 31st Annual Boston University Conference on Language Development (117-128). Somerville, MA:  Cascadilla Press

Soderstrom, M., & Morgan, J. L. (2007) Twenty-two-month-olds discriminate fluent from disfluent adult-directed speech. Developmental Science, 10, 641-653.

Soderstrom, M., White, K. S., Conwell, E. & Morgan, J. L. (2007) Receptive grammatical knowledge of familiar content words and inflection in 16-month-olds. Infancy, 12, 1-29.

Tenenbaum, E., & Morgan, J. L. (2007). Racing to segment? Top-down versus bottom-up in infant word recognition. In H. Caunt-Nulton, S. Kulatilake, & I. Woo (eds.) Proceedings of the 31st Annual Boston University Conference on Language Development (pp. 620-631). Somerville, MA:  Cascadilla Press.

Blossom, M., & Morgan, J. L. (2006). Does the face say what the mouth says? A study of infants’ sensitivity to visual prosody. In D. Bamman, T. Magnitskaia, & C. Zaller (Eds.) Proceedings of the 30th Annual Boston University Conference on Language Development (pp. 24-35). Somerville, MA:  Cascadilla Press.

Bortfeld, H., Morgan, J. L., Golinkoff, R. M., & Rathbun, K. (2005). Mommy and me: Familiar names help launch babies into speech stream segmentation. Psychological Science, 16, 298-307.

Singh, L., Morgan, J., White, K. (2004). Preference and processing: The role of speech affect in early spoken word recognition. Journal of Memory and Language, Vol 51(2), 173-189.

Soderstrom, M., Seidl, A., Kemler Nelson, D. G., & Jusczyk, P.W. (2003). The prosodic bootstrapping of phrases: Evidence from prelinguistic infants. Journal of Memory and Language, 49, 249-267. (work done at Johns Hopkins University)

Anderson, J., Morgan, J., White, K. (2003). A Statistical Basis for Speech Sound Discrimination. Language and Speech, Vol 46 (2-3), 155-182.

Singh, L., Morgan, J. L., & Best, C. (2002). Infants' listening preferences: Baby talk or happy talk? Infancy, 3, 365-394.

Shi, R., Werker, J. F., & Morgan, J. L. (1999). Newborn infants' sensitivity to perceptual cues to lexical and grammatical words. Cognition, B11-21.

Shi, R., Morgan, J. L., & Allopenna, P. (1998). Phonological and acoustic bases for early grammatical category assignment: A cross-linguistic perspective. Journal of Child Language, 25, 169-201.

Morgan, J. L. (1996). A rhythmic bias in preverbal speech segmentation. Journal of Memory and Language, 33, 666-689.

Morgan, J. L. (1996). Prosody and the roots of parsing. Language and Cognitive Processes, 11, 69-106.

Morgan, J. L. & Demuth, K. D. (Eds.) (1996). Signal to syntax: Bootstrapping from speech to grammar in early language acquisition. Mahwah, NJ: Lawrence Erlbaum Associates.

Morgan, J. L., Bonamo, K. M., & Travis, L. L. (1995). Negative evidence on negative evidence. Developmental Psychology, 31, 180-197.

Morgan, J. L., & Saffran, J. R. (1995). Emerging integration of sequential and suprasegmental information in preverbal speech segmentation. Child Development, 66, 911-936.

Fogarty Senior International Fellow 2000-2001 (France)
Fulbright Senior Scholar 2001 (France)

Society for Research in Child Development
International Society for Infant Studies
Society for Language Development