Biomedical subjects

Sachiyo Kajikawa

Publications and source records attributed to Sachiyo Kajikawa.

5 recordsLinked to original sources

PubMed2006

Infant-directed speech supports phonetic category learning in English and Japanese.

Across the first year of life, infants show decreased sensitivity to phonetic differences not used in the native language [Werker, J. F., & Tees, R. C. (1984). Cross-language speech perception: evidence for perceptual reorganization during the first year of life. Infant Behaviour and Development, 7, 49-63]. In an artificial language learning manipulation, Maye, Werker, and Gerken [Maye, J., Werker, J. F., & Gerken, L. (2002). Infant sensitivity to distributional information can affect phonetic discrimination. Cognition, 82(3), B101-B111] found that infants change their speech sound categories as a function of the distributional properties of the input. For such a distributional learning mechanism to be functional, however, it is essential that the input speech contain distributional cues to support such perceptual learning. To test this, we recorded Japanese and English mothers teaching words to their infants. Acoustic analyses revealed language-specific differences in the distributions of the cues used by mothers (or cues present in the input) to distinguish the vowels. The robust availability of these cues in maternal speech adds support to the hypothesis that distributional learning is an important mechanism whereby infants establish native language phonetic categories.

Canada↗

PubMed2006

Cross-language sensitivity to phonotactic patterns in infants.

This study explored sensitivity to word-level phonotactic patterns in English and Japanese monolingual infants. Infants at the ages of 6, 12, and 18 months were tested on their ability to discriminate between test words using a habituation-switch experimental paradigm. All of the test words, neek, neeks, and neekusu, are phonotactically legitimate for English, whereas the first two words are critically noncanonical in Japanese. The language-specific phonotactical congruence influenced infants' performance in discrimination. English-learning infants could discriminate between neek and neeks at the age of 18 months, but Japanese infants could not. There was a similar developmental pattern for infants of both language groups for discrimination of neek and neeks, but Japanese infants showed a different trajectory from English infants for neekusu/neeks. These differences reflect the different status of these word patterns with respect to the phonotactics of both languages, and reveal early sensitivity to subtle phonotactic and language input patterns in each language.

Acoustic Stimulation↗

PubMed2005

Japanese listeners' perceptions of phonotactic violations.

The canonical form for Japanese words is (Consonant)Vowel(Consonant) Vowel-. However, a regular process of high vowel devoicing between voiceless consonants and word-finally after voiceless consonants results in consonant clusters and word-final consonants, apparent violations of that phonotactic pattern. We investigated Japanese adults' perceptions of these violations, asking them to rate both canonical and noncanonical nonsense forms on a scale of goodness. Results indicate that adults show evidence of being guided in making their judgments by an implicit understanding of both typical canonical forms and appropriate contexts for vowel devoicing.

Adult↗

PubMed2004

Speech overlap in Japanese mother-child conversations.

This study aimed to clarify the development of conversational style in Japanese mother-child interactions. We focused on the frequency of speech overlap as an index of Japanese conversational style, with particular attention to ne, a particle produced by the speaker, and to backchannels, such as 'uh-huh', produced by the listener that support sympathetic conversation. The results of longitudinal observations of two Japanese mother-child dyads from approximately 0;11 to 3;3 suggest that an adultlike conversational style with frequent overlaps emerges in Japanese child-directed speech around the two-word utterance period, and a child's development of ne use is closely related to this shift.

Child Language↗

PubMed2003

[Recognition of sound pattern of words extracted from spoken sentences by preverbal infants].

The present experiment investigated the ability of recognition and long-term retention of sound pattern of words extracted from spoken sentences in preverbal infants. When preferences of 8-month-old Japanese infants for target words and for novel words were tested by head-turn preference procedure, immediately after being auditory exposed to spoken sentences that included the target words, they showed preference for target words significantly over novel words. They were able to recognize words that were presented within sentences previously. Moreover, such preference was confirmed when the infants were tested with a 2-week interval. On the other hand, their preference for prosodic properties of the exposed spoken sentences was not confirmed. Infants retain information of those words that were extracted from the speech analytically rather than holistically.

Female↗