Nonlinear development of speaking rate in child-directed speech

The current study investigated if the speaking rate in Child-Directed Speech (CDS) changes over the course of child language development, and, if so, what the nature of that change is. The developmental path of CDS speaking rate was analyzed in 25 mother-child pairs from longitudinal corpora in CHILDES database. The results were then compared with the developmental pattern of speaking rate in child-produced speech. A parallel analysis was made on the development of mean length of utterance (MLU) in mother and child. The findings suggest that CDS speaking rate dynamically changes with shifts occurring around the onset of child speech production and again during the multiword stage. A parallel pattern of nonlinearity was also observed in the speaking rate of the child and the MLU of both mother and child. Phonological precision effects in CDS (e.g. exaggerated VOT) are explained as a by-product of varying speaking rate. Implications of the findings for studies of language acquisition are discussed

An Information-Status Theory of Case and NP Deletion in Korean : With a Focus on the Realization of Object

This paper examines the realization of the object and object case marker in Korean by means of a Quantitative analysis of naturally occurring data, and provides a unified analysis of what determines the optional or obligatory realization of objects and the object marker through the information status theory of Prince (1992), the cognitive hierarchy theory of Gundel et al. (1993) and a focus theory of Vallduvi and Vilkuna (1998). In a statistical analysis of the data, it is shown that the realization of the object and object case marker in Korean is closely related to the formality of the speech. It is also proposed that the object case marker -lul is a delimiter that conveys kontrastive function, evoking a set of alternative members. This paper provides a typological addition to ways of information packaging by showing that morphology is exploited for conveying information in Korean while some languages mainly exploit syntax and/or prosody

Korean Mothers Attune the Frequency and Acoustic Saliency of Sound Symbolic Words to the Linguistic Maturity of Their Children

The present study investigates Korean mothers’ use of sound symbolism, in particular expressive lengthening and ideophones, in their speech directed to their children. Specifically, we explore whether the frequency and acoustic saliency of sound symbolic words are modulated by the maturity of children’s linguistic ability. A total of 36 infant-mother dyads, 12 each belonging to the three groups of preverbal (M = 8-month-old), early speech (M = 13-month-old), and multiword (M = 27-month-old) stage, were recorded in a 40-min free-play session. The results were consistent with the findings in previous research that the ratio of sound symbolic words in mothers’ speech decreases with child age and that they are acoustically more salient than conventional words in duration and pitch measures. We additionally found that mothers weaken the prominence for ideophones for older children in mean pitch, suggesting that such prominence of these iconic words might bootstrap infants’ word learning especially when they are younger. Interestingly, however, we found that mothers maintain the acoustic saliency of expressive lengthening consistently across children’s ages in all acoustic measures. There is some indication that children at age 2 are not likely to have mastered the fine details of scalar properties in certain words. Thus, it could be that they still benefit from the enhanced prosody of expressive lengthening in learning the semantic attributes of scalar adjectives, and, accordingly, mothers continue to provide redundant acoustic cues longer for expressive lengthening than ideophones

Bracketing Guidelines for Penn Korean TreeBank

This document describes the syntactic bracketing guidelines for the Penn Korean Treebank, which is an online corpus of Korean texts annotated with morphological and syntactic information. The corpus consists of around 54,000 words and 5,000 sentences. The Treebank uses a phrase structure style of annotation, making head/phrasal node distinctions, argument/adjunct distinctions, and identifying empty arguments and traces for moved constituents. This document is organized as follows. In section 2, the basic syntactic ingredients of a clause structure are presented. Some notational conventions are introduced in section 3, including different types of syntactic tags, such as head level tags, phrase level tags and function tags used in the Treebank. In section 4, the bracketing guidelines for various types of clauses are discussed, including simple clauses, subordinate clauses, and clauses with coordination. Several types of subcategorizaion frames found in the Treebank are then presented in section 5, followed by bracketing guidelines for various linguistic phenomena in sections 6 to 21, including guidelines for annotating punctuation. The document ends with guidelines for handling some bracketing ambiguities and for handling some confusing examples

Quantifying sources of variability in infancy research using the infant-directed-speech preference

Psychological scientists have become increasingly concerned with issues related to methodology and replicability, and infancy researchers in particular face specific challenges related to replicability: For example, high-powered studies are difficult to conduct, testing conditions vary across labs, and different labs have access to different infant populations. Addressing these concerns, we report on a large-scale, multisite study aimed at (a) assessing the overall replicability of a single theoretically important phenomenon and (b) examining methodological, cultural, and developmental moderators. We focus on infants’ preference for infant-directed speech (IDS) over adult-directed speech (ADS). Stimuli of mothers speaking to their infants and to an adult in North American English were created using seminaturalistic laboratory-based audio recordings. Infants’ relative preference for IDS and ADS was assessed across 67 laboratories in North America, Europe, Australia, and Asia using the three common methods for measuring infants’ discrimination (head-turn preference, central fixation, and eye tracking). The overall meta-analytic effect size (Cohen’s d) was 0.35, 95% confidence interval = [0.29, 0.42], which was reliably above zero but smaller than the meta-analytic mean computed from previous literature (0.67). The IDS preference was significantly stronger in older children, in those children for whom the stimuli matched their native language and dialect, and in data from labs using the head-turn preference procedure. Together, these findings replicate the IDS preference but suggest that its magnitude is modulated by development, native-language experience, and testing procedure. (This project has received funding from the European Union’s Horizon 2020 research and innovation programme under the Marie Skłodowska-Curie grant agreement No 798658.

The phonology and phonetics of word -level prosody and its interaction with phrase -level prosody: A study of Korean in comparison to English

This thesis investigates the following research questions: (1) Does Korean have a metrical structure? (2) If so, what are its acoustic correlates and how do they compare to English? (3) How does it interact with phrasal prosody? In addressing these issues, I first re-examine the identity of the so-called “long” vowel in Korean, and argue that it is a phonetic duration derived from an underlying accent on surface. The phonological argument is based on a reanalysis of what has been traditionally called “vowel shortening” in verb stems and compounds as “accent shift”. I describe phonetic experiments to verify the proposed phonological analysis, comparing the acoustic properties of the so-called “long” and “short” (i.e. stressed and unstressed) vowels of Korean. To compare the results with a well-known stress system, I describe a parallel experiment on English. I employ the following two experimental methods: (1) The location of the target word is varied in three different prosodic positions. (2) The data are analyzed with two complementary methods: Direct Comparison Method (e.g. ‘per’ of ‘perMIT’ vs. ‘PER’ of ‘PERmit’) and Relative Comparison Method (e.g. ‘per’ of ‘perMIT’ vs. ‘MIT’ of ‘perMIT’). The overall results suggest that both Korean and English adopt longer duration, higher fundamental frequency, and greater intensity for the stressed vowels. However, they differ in the details: (1) Korean has a greater phrase final lengthening effect than English. (2) In Korean, the phrase initial rising tone dominates the effects of stress. (3) Pitch plays a more important role in English than in Korean. Finally, I investigate the phrasal prosody and argue the following: (1) Intensification and focus use different phonetic cues (duration and pitch movement, respectively), but both of them respect metrical structure. (2) Vocative chant reflects the special status of the stressed syllable in duration and pitch. In the conclusion, implications of the proposed theory are discussed on deriving the prosodic hierarchy of Korean and the prosodic typology