Theses and Dissertations from UMD

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Subject: search.filters.subject.infant-directed speech

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    Evaluating the role of acoustic cues in identifying the presence of a code-switch
    (2024) Exton, Erika Lynn; Newman, Rochelle S.; Hearing and Speech Sciences; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)
    Code-switching (switching between languages) is a common linguistic behavior in bilingual speech directed to infants and children. In adult-directed speech (ADS), acoustic-phonetic properties of one language may transfer to the other language close to a code-switch point; for example, English stop consonants may be more Spanish-like near a switch. This acoustically-natural code-switching may be easier for bilingual listeners to comprehend than code-switching without these acoustic changes; however, it effectively results in the languages being more phonetically similar at the point of a code-switch, which could make them difficult for an unfamiliar listener to distinguish. The goal of this research was to assess the acoustic-phonetic cues to code-switching available to listeners unfamiliar with the languages by studying the perception and production of these cues. In Experiment 1 Spanish-English bilingual adults (particularly those who hear code-switching frequently), but not English monolingual adults, were sensitive to natural acoustic cues to code-switching in unfamiliar languages and could use them to identify language switches between French and Mandarin. Such cues were particularly helpful when they allowed listeners to anticipate an upcoming language switch (Experiment 2). In Experiment 3 monolingual children appeared unable to continually identify which language they were hearing. Experiment 4 provides some preliminary evidence that monolingual infants can identify a switch between French and Mandarin, though without addressing the utility of natural acoustic cues for infants. The acoustic detail of code-switched speech to infants was investigated to evaluate how acoustic properties of bilingual infant-directed speech (IDS) are impacted by the presence of and proximity to code-switching. Spanish-English bilingual women narrated wordless picture books in IDS and ADS, and the voice onset times of their English voiceless stops were analyzed in code-switching and English-only stories in each register. In ADS only, English voiceless stops that preceded an English-to-Spanish code-switch and were closer to that switch point were produced with more Spanish-like voice onset times than more distant tokens. This effect of distance to Spanish on English VOTs was not true for tokens that followed Spanish in ADS, or in either direction in IDS, suggesting that parents may avoid producing these acoustic cues when speaking to young children.
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    Infant-Directed Speech: Maternal Pitch Variability, Rate of Speech, and Child Language Outcomes
    (2015) Raneri, Daniele Palma; Ratner, Nan B; Hearing and Speech Sciences; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)
    Research regarding the influence of specific features typical of infant-directed speech (IDS) and their potential role in facilitating children’s language development is still needed. Very little evidence links features of IDS to specific or general language outcomes. Surprisingly, given their pervasive description, the potential impacts of slowed speech rate and increased pitch variability of IDS on child language outcomes have not been examined. This study asks whether decreased speech rate and increased pitch variability in IDS among 42 mother-infant dyads at 7, 10/11, 18, and 24 months predicts language outcomes at two years. Decreased maternal speech rate at seven months related to increased child expressive language outcomes at two years. Contrary to hypotheses, children who were exposed to IDS characterized by decreased pitch variability at seven months had greater expressive language outcomes at two years than children who were exposed to IDS with increased pitch variability. Possible interpretations and clinical ramifications are discussed.
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    PATTERNS AND POSSIBLE INFLUENCES OF MATERNAL VOWEL CLARIFICATION ON CHILD LANGUAGE DEVELOPMENT
    (2013) Hartman, Kelly Marie; Ratner, Nan B; Hearing and Speech Sciences; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)
    There have been many studies examining the differences between infant-directed speech (IDS) and adult-directed speech (ADS). However, very few longitudinal studies exist that explore how patterns of maternal vowel articulation in IDS change as children get older, or whether these changes have any effect on a child's developing language skills. This study examines the vowel clarification of mothers' IDS at 10-11 months, 18 months, and 24 months, as compared to their vowel production in ADS. Relationships between vowel space, vowel duration, and vowel variability and child language outcomes at 2 years are also explored. Results show that vowel space and vowel duration tend to be greater in IDS than in ADS, and that a mother's vowel space at 18 months is significantly related to expressive and receptive child language outcomes at 2 years. Possible explanations are discussed.
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    Infant Preferences for Two Properties of Infant-Directed Speech
    (2010) Segal, Judith Lee; Newman, Rochelle S; Hearing and Speech Sciences; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)
    This study examined preferences for prosodic and structural properties of infant-directed speech (IDS) in 20 infants, 11 girls and 9 boys, ages 0;11;3 to 0;13;0 (mean age 0;11;28). It was hypothesized that year-old infants would demonstrate a preference for infant-directed structure (IS) over adult-directed structure (AS) regardless of prosody, and that infants would demonstrate no preference for either infant-directed prosody (IP) or adult-directed prosody (AP) regardless of structure. Listening times to passages were compared across infants for four conditions: IS/IP; IS/AP; AS/IP; AS/AP. Results indicate a non-significant but noticeable trend toward a preference for infant-directed structure. In addition, weak correlations were found between vocabulary size and strength of preference for adult-directed prosody, and between age and strength of preference for adult-directed prosody. A non-significant but noticeable interaction was found between prosody and structure and vocabulary. Overall, infants appear to prefer listening to infant-directed structure to adult-directed structure; more advanced language learners show a stronger preference for adult-directed prosody than do their less advanced age-mates; older infants show a stronger preference for adult-directed prosody than do younger infants; and preference for infant-directed structure (but not infant-directed prosody) depends on vocabulary level.