Wednesday (Tuesday!) Seminar: Early perception of lexical tones by non-tone-learning infants

René Kager, Professor of Phonology and Language Acquisition at Utrecht University, will give a talk on early perception of lexical tones.

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Infants start with a general sensitivity to speech sounds. Initially they can discriminate a wide range of phonetic contrasts that do not exist in their native language. Between 6 and 10 months of age, infants’ discrimination of non-native contrasts declines, while their discrimination of native contrasts increases. This process is called perceptual attunement (PA). Most previous work on PA has focused on consonants or vowels, but a rapidly growing body of studies considers PA for lexical tone. 

Languages may contrast tones at different levels. For intonation, tone is contrastive at the utterance level. For lexical tone, tones contrast at the word level (only in tone languages). Crucially, intonation and lexical tone are both marked by variation in pitch (fundamental frequency, F0), which raises the issue how infants learn to disentangle pitch contrasts at the word level from pitch at the utterance level (Kager, 2018). 

Neonates are universally sensitive to pitch contours (Nazzi et al., 1998). Yet as early as 4–6 months, differences in tone perception are observed between infants acquiring a tone language and infants who are not (Yeung et al., 2013). Tone-learning infants retain their initial ability to discriminate tone, whereas infants learning a non-tone language lose their discrimination around 6-9 months (Mattock & Burnham, 2006; Mattock et al., 2008; Yeung et al., 2013; Liu & Kager, 2014), their use of pitch for word recognition by 10 months (Singh et al., 2004; Singh, 2008; Singh et al., 2008) and their ability to learn tone-to-word associations by 18 months (Quam & Swingley, 2010; Hay et al., 2015; Liu & Kager, 2018).

Research at the BabyLab Utrecht in collaboration with Liquan Liu and Ao Chen has investigated PA for lexical tone by tracking the development of tone perception in Dutch non-tone-learning (NTL) infants during the two years of life. We are considering questions such as the following: How does sensitivity to tone develop after 9 months? Do NTL infants permanently lose their sensitivity to tone, while not losing their sensitivity to intonation? How irreversible are the effects of tonal PA? How is tonal PA related to developing knowledge of intonation? How does phonetic salience of pitch contrasts affect tonal PA? How does tonal PA affect word learning ability? How does bilingualism affect NTL infants’ tone perception ability? How are pitch perception and musical perception related in NTL infants? Is pitch perception in NTL infants affected by cognitive maturation as well as exposure? In this talk I will present an overview the results of recent studies (2014-2018) which addressed these questions. 

Our results converge to show that the acoustic sensitivity and phonological sensitivity to non-native tones slowly dissociate from the second year of life onward. Infants’ discrimination of a non-native tone contrast shows a U-shaped pattern, with an increase of tone discrimination early in the second year of life. Bilingual NTL infants show a pattern of facilitation: their sensitivity to tones is enhanced and re-emerges earlier as compared to monolinguals. We also found evidence that tone perception is  subject to cognitive maturation, independently of exposure. Regarding word learning, infants’ ability to use the same tone contrast shows a declining pattern, in monolinguals and bilingual infants alike. In sum, halfway their second year of life, NTL infants’ acoustic sensitivity to pitch variation increases, yet the linguistic (phonological) function lost. 



Chen, A., & Kager, R. (2016). Discrimination of lexical tones in the first year of life. Infant and Child Development25(5), 426-439.

Chen, A., Stevens, C. J., & Kager, R. (2017). Pitch perception in the first year of life: A comparison of lexical tones and musical pitch. Frontiers in Psychology8, 297.

Hay, J. F., Graf Estes, K., Wang, T., & Saffran, J. R. (2015). From flexibility to constraint: The contrastive use of lexical tone in early word learning. Child Development86(1), 10-22.

Kager, R. (2018). How do infants disaggregate referential and affective pitch? Frontiers in Psychology9, 2093.

Liu, L. & Kager, R. (2018). Monolingual and bilingual infants’ ability to use non-native tone for word learning deteriorates by the second year after birth. Frontiers in Psychology9, 117. 

Liu, L., & Kager, R. (2014). Perception of tones by infants learning a non-tone language. Cognition133(2), 385-394.

Liu, L., & Kager, R. (2017). Enhanced music sensitivity in 9-month-old bilingual infants. Cognitive Processing18(1), 55-65.

Liu, L., & Kager, R. (2017). Perception of tones by bilingual infants learning non-tone languages. Bilingualism: Language and Cognition20(3), 561-575.

Liu, L., & Kager, R. (2017). Statistical learning of speech sounds is most robust during the period of perceptual attunement. Journal of Experimental Child Psychology164, 192-208. 

Mattock, K., & Burnham, D. (2006). Chinese and English infants' tone perception: evidence for perceptual reorganization, Infancy10(3), 24-265, 2006.

Mattock, K., Molnar, M., Polka, L., & Burnham, D. (2008). The developmental course of lexical tone perception in the first year of life, Cognition106, 1367–1381.

Nazzi, T., Floccia, C., & Bertoncini, J. (1998). Discrimination of pitch contours by neonates, Infant Behavior and Development21, 779–784.

Quam, C., & Swingley, D. (2010). Phonological knowledge guides 2-year-olds’ and adults’ interpretation of salient pitch contours in word learning. Journal of Memory and Language62(2), 135-150.

Singh, L. (2008). Influences of high and low variability on infant word recognition. Cognition106(2), 833-870.

Singh, L., Morgan, J.L., & White, K.S. (2004). Preference and processing: The role of speech affect in early spoken word recognition. Journal of Memory and Language51(2), 173-189.

Singh, L., White, K.S., & Morgan, J.L. (2008). Building a word-form lexicon in the face of variable input: Influences of pitch and amplitude on early spoken word recognition. Language Learning and Development4(2), 157-178.

Yeung, H. H., Chen, K. H., & Werker, J. F. (2013). When does native language input affect phonetic perception? The precocious case of lexical tone. Journal of Memory and Language68(2), 123-139.


René Kager is Professor of Phonology and Language Acquisition at Utrecht University. He received his Ph.D. (1989) in the Netherlands, and then taught at UCLA and Stanford University before returning to Utrecht. In his theoretical work, he focuses on metrical word stress and phonotactics in constraint-based models of phonology. In his acquisition work, he addresses the perception of tone, rhythm and segmental contrasts in monolingual and bilingual infants. He is also involved in modelling aspects of phonological acquisition, using artificial language learning studies and computational modelling. He is the author of a well-known textbook on Optimality Theory (CUP, 1999), and has published in major journals, including Journal of Memory & LanguageCognition and Linguistic Inquiry. He has received several large grants, including a VICI grant from the Netherlands Organisation for Scientific Research (NWO, 2005-2010) on the acquisition of phonotactic constraints for speech segmentation. Currently, he is a PI in the Consortium on Individual Development (NWO).


Liquan Li and Yesim Sevinc
Published Oct. 15, 2019 11:47 AM - Last modified Mar. 16, 2021 9:32 AM