166 research outputs found

    Lexical and Prosodic Pitch Modifications in Cantonese Infant-directed Speech

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    Published online 03 February 2021The 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. Similar findings were observed in speech to pets who should not benefit from larger phonemic distinction. We conclude that lexicaltone adjustments in IDS mainly serve to broadly enhance communication rather than specifically increase phonemic contrast for learners.This work was supported by the University Grants Committee (HKSAR) (RGC34000118), the Innovation and Technology Fund (HKSAR) (ITS/067/18), Dr. Stanley Ho Medical Development Foundation, and the Global Parent Child Resource Centre Limited. The second author’s work is supported by the Basque Government through the BERC 2018-2021 program and by the Spanish Ministry of Science and Innovation through the Ramon y Cajal Research Fellowship, PID2019-105528GA-I00

    Infants’ Sensitivity to Lexical Tone and Word Stress in Their First Year: A Thai and English Cross- Language Study

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    Published online: 23 Aug 2021Non-tone language infants’ native language recognition is based first on supra-segmental then segmental cues, but this trajectory is unknown for tone-language infants. This study investigated non-tone (English) and tone (Thai) language 6- to 10-month-old infants’ preference for English vs. Thai one-syllable words (containing segmental and tone cues) and two-syllable words (additionally containing stress cues). A preference for their native onesyllable words was observed in each of the two groups of infants, but this was not the case for two-syllable words where Thai-learning infants showed no native-language preference. These findings indicate that as early as six months of age, infants acquiring tone- and non-tone languages identify their native language by relying solely on lexical tone cues, but tone language infants no longer show successful identification of their native language when two pitch-based cues co-occur in the signal.The first author’s work was supported by the European Union’s Horizon 2020 Marie Sklodowska-Curie individual Fellowships European Programme under Grant Agreement No 798908 Optimising IDS, and she receives support from the Basque Government through the BERC 2018–2021 program, and from the Spanish Ministry of Science and Innovation through the Ramon y Cajal Research Fellowship, PID2019–105528GA-I00

    The listening talker: A review of human and algorithmic context-induced modifications of speech

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    International audienceSpeech output technology is finding widespread application, including in scenarios where intelligibility might be compromised - at least for some listeners - by adverse conditions. Unlike most current algorithms, talkers continually adapt their speech patterns as a response to the immediate context of spoken communication, where the type of interlocutor and the environment are the dominant situational factors influencing speech production. Observations of talker behaviour can motivate the design of more robust speech output algorithms. Starting with a listener-oriented categorisation of possible goals for speech modification, this review article summarises the extensive set of behavioural findings related to human speech modification, identifies which factors appear to be beneficial, and goes on to examine previous computational attempts to improve intelligibility in noise. The review concludes by tabulating 46 speech modifications, many of which have yet to be perceptually or algorithmically evaluated. Consequently, the review provides a roadmap for future work in improving the robustness of speech output

    Acoustic features of infant-directed speech to infants with hearing loss

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    Published Online: 03 December 2020This study investigated the effects of hearing loss and hearing experience on the acoustic features of infant-directed speech (IDS) to infants with hearing loss (HL) compared to controls with normal hearing (NH) matched by either chronological or hearing age (experiment 1) and across development in infants with hearing loss as well as the relation between IDS features and infants' developing lexical abilities (experiment 2). Both experiments included detailed acoustic analyses of mothers' productions of the three corner vowels /a, i, u/ and utterance-level pitch in IDS and in adult-directed speech. Experiment 1 demonstrated that IDS to infants with HL was acoustically more variable than IDS to hearing-age matched infants with NH. Experiment 2 yielded no changes in IDS features over development; however, the results did show a positive relationship between formant distances in mothers' speech and infants' concurrent receptive vocabulary size, as well as between vowel hyperarticulation and infants' expressive vocabulary. These findings suggest that despite infants' HL and thus diminished access to speech input, infants with HL are exposed to IDS with generally similar acoustic qualities as are infants with NH. However, some differences persist, indicating that infants with HL might receive less intelligible speech.This research was supported by HEARing Cooperative Research Centre Grant No. 82631, “The Seeds of Language Development,” to D.B. The second author's work is supported by the Basque Government through the BERC 2018-2021 program and by the Spanish Ministry of Science and Innovation through the Ramon y Cajal Research Fellowship PID2019-105528GA-I00. We would like to thank all the parents and infants for participating in the study; “The Shepherd Centre” in Sydney and Wollongong; “Hear and Say” in Brisbane for their help in recruitment of participants with HL; and Benjawan Kasisopa, Maria Christou-Ergos, Hana Zjakic, and Scott O'Loughlin for their assistance with data collection

    Perceptual reorganization of lexical tones : effects of age and experimental procedure

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    Findings on the perceptual reorganization of lexical tones are mixed. Some studies report good tone discrimination abilities for all tested age groups, others report decreased or enhanced discrimination with increasing age, and still others report U-shaped developmental curves. Since prior studies have used a wide range of contrasts and experimental procedures, it is unclear how specific task requirements interact with discrimination abilities at different ages. In the present work, we tested German and Cantonese adults on their discrimination of Cantonese lexical tones, as well as German-learning infants between 6 and 18 months of age on their discrimination of two specific Cantonese tones using two different types of experimental procedures. The adult experiment showed that German native speakers can discriminate between lexical tones, but native Cantonese speakers show significantly better performance. The results from German-learning infants suggest that 6-and 18-month-olds discriminate tones, while 9-month-olds do not, supporting a U-shaped developmental curve. Furthermore, our results revealed an effect of methodology, with good discrimination performance at 6 months after habituation but not after familiarization. These results support three main conclusions. First, habituation can be a more sensitive procedure for measuring infants' discrimination than familiarization. Second, the previous finding of a U-shaped curve in the discrimination of lexical tones is further supported. Third, discrimination abilities at 18 months appear to reflect mature perceptual sensitivity to lexical tones, since German adults also discriminated the lexical tones with high accuracy

    The role of infant-directed speech in language development of infants with hearing loss

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    It is estimated that approximately two out of every 1000 infants worldwide are born with unilateral or bilateral hearing loss (HL). Congenital HL, which refers to HL present at birth, has major negative effects on infants’ speech and language acquisition. Although such negative effects can be mediated by early access to hearing devices and intervention, the majority of children with HL have delayed language development in comparison with their normal-hearing (NH) peers. The aim of this thesis was to provide a deeper empirical understanding of the acoustic features in infant-directed speech (IDS) to infants with HL compared to infants with NH of the same chronological and the same hearing age. The three specific objectives were set for this thesis. The first objective is to investigate the effects of HL and the degree of hearing experience on the acoustic features of IDS. The second objective is to assess adjustments in IDS features across development in IDS to infants with HL, as they acquire more hearing experience. The third objective is to evaluate the role of specific IDS components such as vowel hyperarticulation and exaggerated prosody in lexical processing in infants with NH from six to 18 months of age, at both neural and behavioural levels. This was achieved by conducting four experiments. The first experiment used a cross-sectional design that assessed the acoustic features in IDS to infants with HL with a specific focus on whether and how infants’ chronological age and hearing age may affect these features. Experiment 2 included a longitudinal investigation that focused on the acoustic features of IDS to infants with HL and infants with NH of the same hearing age. We sought to identify how infants’ changing linguistic needs may shape maternal IDS across development. Experiments 3 and 4 focused on lexical processing in six-, 10-, and 18-month-old infants, whereby we aimed to identify the role of specific IDS features in facilitating lexical processing in infants with NH at different stages of language acquisition. The results of this thesis demonstrated that mothers adjust their IDS to infants with HL in a similar manner as in IDS to infants with NH. However, some differences are evident in the production of the corner vowels /i/ and /u/. These differences exist even when controlling for the amount of hearing experience had by infants with HL. Additionally, findings demonstrated a relation between vowel production in IDS and infants’ receptive vocabulary indicating that the exaggeration in vowel production in maternal IDS may play a fostering role in infants’ language acquisition. This linguistic role was confirmed as vowel hyperarticulation was also found to facilitate lexical processing at the neural level in 10-month-old infants. However, with regard to older infants (18 months), our findings demonstrated that natural IDS with heightened pitch and vowel hyperarticulation represents the richest input that facilitates infants’ speech processing. In summary, the findings of this thesis suggest that congenital HL in infants affects maternal production of vowels in IDS resulting in less clear vowel categories. This may result from mothers adjusting their vowel production according to infants’ reduced vowel discrimination abilities, thus, adjusting their IDS to infants’ linguistic competence. Additionally, receptive vocabulary seems not to be affected by this, indicating the role of other cues for building a lexicon in infants with HL that warrant further investigation. Furthermore, the findings suggest that pitch and vowel hyperarticulation in IDS play significant roles in facilitating lexical processing in the first two years of life

    Vocalic Intrusions in Consonant Clusters in Child-Directed vs. Adult-Directed Speech.

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    In this paper, we investigate a prosodic-phonetic feature in child-directed speech within a dynamic, complex, interactive theoretical framework. We focus on vocalic intrusions, commonly occurring in Norwegian word initial consonant clusters. We analysed child-directed speech from nine Norwegian-speaking mothers to their children, aged 2;6, 4, and 6 years, and compared the incidence and duration of vocalic intrusions in initial consonant clusters in these data with those in adult-directed speech and child speech. When viewed overall, vocalic intrusion was found to be similar in incidence in child- and adult-directed speech. However, closer examination revealed differential behaviour in child-directed speech for certain conditions. Firstly, a difference emerged for one particular phonetic context: While vocalic intrusions in /Cr/ clusters are frequent in adult-directed speech, their presence is near-categorical in child-directed speech. Secondly, we found that the duration of vocalic intrusions was longer in child- than in adult-directed speech, but only when directed to 2;6-year-olds. We argue that vocalic intrusions in child-directed speech may have both a bonding as well as a didactic function, and that these may vary according to the age of the child being addressed
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