Publications by authors named "Rene Kager"

Purpose: Speech sound disorder (SSD) is one of the major speech disorders in school-age children. Given the heterogeneity in terms of subtypes within SSD, there is a need to develop techniques for a quick identification of these subtypes. Furthermore, given the paucity of studies from children with SSD from Cantonese-speaking homes and a noted prevalence of SSDs in Cantonese-speaking children, it becomes even more important to investigate the subtypes of SSDs in Cantonese-speaking children.

View Article and Find Full Text PDF

There is robust evidence that infants' gestures and vocalisations and caregivers' contingent responses predict later child vocabulary. Recent studies suggest that dyadic combinations of infants' behaviors and caregivers' responses are more robust predictors of children's vocabularies than these behaviors separately. Previous studies have not yet systematically compared different types of dyadic combinations.

View Article and Find Full Text PDF

Limited studies have examined demographic differences in children's vocabulary in longitudinal samples, while there are questions regarding the duration, direction, and magnitude of these effects across development. In this longitudinal study, we included over 400 Dutch children. Caregivers filled out N-CDIs when children were 9-11 months (measuring word comprehension, word production, and gestures) and around 2-5 years of age (measuring word production).

View Article and Find Full Text PDF

We consider two asymmetries reported in the literature on word prosodic systems: the tendency to allow more prosodic contrast in nouns than in verbs and the tendency to avoid stress on functional material. We focus on the interaction between these two tendencies and propose a formal mechanism to handle this interaction couched in Optimality Theory. In a case study on a group of standard Serbo-Croatian varieties that have predictable stress in verbs but contrastive stress in nouns, we develop an analysis of predictable and morphologically conditioned stress assignment.

View Article and Find Full Text PDF
Article Synopsis
  • The study investigates how young infants discriminate lexical tones based on their native language, age, language experience, and tone properties, revealing important insights into language learning.
  • Conducted across 13 laboratories globally, it involved testing monolingual and bilingual infants aged 5 to 17 months using the same experimental setup focused on Cantonese tone contrasts.
  • Results show that while infants not exposed to Cantonese effectively discriminated between non-native tone contrasts, Cantonese-learning infants did not demonstrate significant native discrimination, suggesting persistent tone sensitivity in infants and challenging current theories on perceptual narrowing.
View Article and Find Full Text PDF

Caregivers use a range of verbal and nonverbal behaviours when responding to their infants. Previous studies have typically focused on the role of the caregiver in providing verbal responses, while communication is inherently multimodal (involving audio and visual information) and bidirectional (exchange of information between infant and caregiver). In this paper, we present a comprehensive study of caregivers' verbal, nonverbal, and multimodal responses to 10-month-old infants' vocalisations and gestures during free play.

View Article and Find Full Text PDF

This study examines correlations between the prosody of infant-directed speech (IDS) and children's vocabulary size. We collected longitudinal speech data and vocabulary information from Dutch mother-child dyads with children aged 18 ( 49) and 24 ( 27) months old. We took speech context into consideration and distinguished between prosody when mothers introduce familiar vs.

View Article and Find Full Text PDF

The ability to map similar sounding words to different meanings alone is far from enough for successful speech processing. To overcome variability in the speech signal, young learners must also recognize words across surface variations. Previous studies have shown that infants at 14 months are able to use variations in word-internal cues (i.

View Article and Find Full Text PDF

This study examines (1) whether infant-directed speech (IDS) facilitates children's word learning compared to adult-directed speech (ADS); and (2) the link between the prosody of IDS in word-learning contexts and children's word learning from ADS and IDS. Twenty-four Dutch mother-child dyads participated when children were 18 and 24 months old. We collect mothers' ADS and IDS at both ages and test children's word learning from ADS and IDS at 24 months.

View Article and Find Full Text PDF

In the current study, we aimed at understanding the effect of exposure to complex input on speech sound development, by conducting a systematic meta-analysis review of the existing treatment-based studies employing complex input in children with speech sound disorders. In the meta-analysis review, using a list of inclusion criteria, we narrowed 280 studies down to 12 studies. Data from these studies were extracted to calculate effect sizes that were plotted as forest plots to determine the efficacy of complexity-based treatment approaches.

View Article and Find Full Text PDF

The functions of acoustic-phonetic modifications in infant-directed speech (IDS) remain a question: do they specifically serve to facilitate language learning via enhanced phonemic contrasts (the hyperarticulation hypothesis) or primarily to improve communication via prosodic exaggeration (the prosodic hypothesis)? The study of lexical tones provides a unique opportunity to shed light on this, as lexical tones are phonemically contrastive, yet their primary cue, pitch, is also a prosodic cue. This study investigated Cantonese IDS and found increased intra-talker variation of lexical tones, which more likely posed a challenge to rather than facilitated phonetic learning. Although tonal space was expanded which could facilitate phonetic learning, its expansion was a function of overall intonational modifications.

View Article and Find Full Text PDF

This study investigates the pitch properties of infant-directed speech (IDS) specific to word-learning contexts in which mothers introduce unfamiliar words to children. Using a semi-spontaneous story-book telling task, we examined (1) whether mothers made distinctions between unfamiliar and familiar words with pitch in IDS compared to adult-directed speech (ADS); (2) whether pitch properties change when mothers address children from 18 to 24 months; and (3) how Mandarin Chinese and Dutch IDS differ in their pitch properties in word-learning contexts. Results show that the mean pitch of Mandarin Chinese IDS was already ADS-like when children were 24 months, but Dutch IDS remained exaggerated in pitch at the same age.

View Article and Find Full Text PDF

This study investigates the link between the perception and production in sound change in progress, both at the regional and the individual level. Two devoicing processes showing regional variation in Dutch are studied: the devoicing of initial labiodental fricatives and of initial bilabial stops. Five regions were selected, to represent different stages of change in progress.

View Article and Find Full Text PDF
Article Synopsis
  • Traditional learning typically progresses from simple to complex elements, but recent studies indicate that starting with complex elements might be more effective for broader learning.
  • In this study, subjects trained with complex speech sounds showed better generalization to both complex and simple speech, whereas those trained with simple sounds only generalized to simple stimuli.
  • Electrophysiological measures revealed that complex stimuli training led to more significant neural changes, suggesting that complex element exposure may enhance overall learning effectiveness compared to simple elements.
View Article and Find Full Text PDF

Infants are faced with a challenge of disaggregating functions of pitch in the ambient language into affective, pragmatic or referential (the latter in tone languages only). This mini review discusses several factors that might facilitate the disaggregation of referential and affective pitch in infancy: acoustic characteristics of infant-directed speech, recognition of vocal affect, facial cues accompanying affective prosody, and lateralization of affective and referential prosody in the brain. It proposes two hypotheses concerning the role of audiovisual cues and brain lateralization.

View Article and Find Full Text PDF

Tonal information is essential to early word learning in tone languages. Although numerous studies have investigated the intonational and segmental properties of infant-directed speech (IDS), only a few studies have explored the properties of lexical tones in IDS. These studies mostly focused on the first year of life; thus little is known about how lexical tones in IDS change as children's vocabulary acquisition accelerates in the second year (Goldfield and Reznick, 1990; Bloom, 2001).

View Article and Find Full Text PDF

Previous studies reported a non-native word learning advantage for bilingual infants at around 18 months. We investigated developmental changes in infant interpretation of sounds that aid in object mapping. Dutch monolingual and bilingual (exposed to Dutch and a second non-tone-language) infants' word learning ability was examined on two novel label-object pairings using syllables differing in Mandarin tones as labels (flat vs.

View Article and Find Full Text PDF

Although statistical learning has been shown to be a domain-general mechanism, its constraints, such as its interactions with perceptual development, are less well understood and discussed. This study is among the first to investigate the distributional learning of lexical pitch in non-tone-language-learning infants, exploring its interaction with language-specific perceptual attunement during the first 2years after birth. A total of 88 normally developing Dutch infants of 5, 11, and 14months were tested via a distributional learning paradigm and were familiarized on a unimodal or bimodal distribution of high-level versus high-falling tones in Mandarin Chinese.

View Article and Find Full Text PDF

Pitch variation is pervasive in speech, regardless of the language to which infants are exposed. Lexical tone is influenced by general sensitivity to pitch. We examined whether the development in lexical tone perception may develop in parallel with perception of pitch in other cognitive domains namely music.

View Article and Find Full Text PDF

Birdsong shows striking parallels with human speech. Previous comparisons between birdsong and human vocalizations focused on syntax, phonology and phonetics. In this review, we propose that future comparative research should expand its focus to include prosody, i.

View Article and Find Full Text PDF

This study explores the influence of bilingualism on the cognitive processing of language and music. Specifically, we investigate how infants learning a non-tone language perceive linguistic and musical pitch and how bilingualism affects cross-domain pitch perception. Dutch monolingual and bilingual infants of 8-9 months participated in the study.

View Article and Find Full Text PDF

Probabilistic phonotactic knowledge facilitates perception, but categorical phonotactic illegality can cause misperceptions, especially of non-native phoneme combinations. If misperceptions induced by first language (L1) knowledge filter second language input, access to second language (L2) probabilistic phonotactics is potentially blocked for L2 acquisition. The facilitatory effects of L2 probabilistic phonotactics and categorical filtering effects of L1 phonotactics were compared and contrasted in a series of cross-modal priming experiments.

View Article and Find Full Text PDF

Linking the discrimination of voice onset time (VOT) in infancy with infant language background, we examine the perceptual changes of two VOT contrasts (/b/-/p/ and /p(h)/-/p/) by Dutch monolingual and bilingual infants from 8 to 15 months of age. Results showed that language exposure and language dominance had a strong impact on monolingual and bilingual infant VOT perceptual patterns. In addition, perceptual turbulence was found at 8-9 months for bilingual infants, and stabilized perception was presented for all infants from 11 months onwards.

View Article and Find Full Text PDF

This article examines the perception of tones by non-tone-language-learning (non-tone-learning) infants between 5 and 18 months in a study that reveals infants' initial sensitivity to tonal contrasts, deterioration yet plasticity of tonal sensitivity at the end of the first year, and a perceptual rebound in the second year. Dutch infants in five age groups were tested on their ability to discriminate a tonal contrast of Mandarin Chinese as well as a contracted tonal contrast. Infants are able to discriminate tonal contrasts at 5-6 months, and their tonal sensitivity deteriorates at around 9 months.

View Article and Find Full Text PDF