Behavioral and Neuroimaging Research of Reading: a Case of Japanese.

Behavioral studies showed that AS, an English-Japanese bilingual, was a skilled reader in Japanese but was a phonological dyslexic in English. This behavioral dissociation was accounted for by the Hypothesis of Transparency and Granularity postulated by Wydell and Butterworth. However, a neuroimaging study using magnetoencephalography (MEG) revealed that AS has the same functional deficit in the left superior temporal gyrus (STG). This paper therefore offers an answer to this intriguing discrepancy between the behavioral dissociation and the neural unity in AS by reviewing existing behavioral and neuroimaging studies in alphabetic languages such as English, Finnish, French, and Italian, and nonalphabetic languages such as Japanese and Chinese.

Speech misperception: speaking and seeing interfere differently with hearing.

Speech perception is thought to be linked to speech motor production. This linkage is considered to mediate multimodal aspects of speech perception, such as audio-visual and audio-tactile integration. However, direct coupling between articulatory movement and auditory perception has been little studied. The present study reveals a clear dissociation between the effects of a listener's own speech action and the effects of viewing another's speech movements on the perception of auditory phonemes. We assessed the intelligibility of the syllables [pa], [ta], and [ka] when listeners silently and simultaneously articulated syllables that were congruent/incongruent with the syllables they heard. The intelligibility was compared with a condition where the listeners simultaneously watched another's mouth producing congruent/incongruent syllables, but did not articulate. The intelligibility of [ta] and [ka] were degraded by articulating [ka] and [ta] respectively, which are associated with the same primary articulator (tongue) as the heard syllables. But they were not affected by articulating [pa], which is associated with a different primary articulator (lips) from the heard syllables. In contrast, the intelligibility of [ta] and [ka] was degraded by watching the production of [pa]. These results indicate that the articulatory-induced distortion of speech perception occurs in an articulator-specific manner while visually induced distortion does not. The articulator-specific nature of the auditory-motor interaction in speech perception suggests that speech motor processing directly contributes to our ability to hear speech.

Reliability of familiarity rating of ordinary Japanese words for different years and places.

Two-word familiarity sets were measured in different years (1995 and 2002) and places (Kanto and Kinki, in Japan) for a large number of Japanese words, to examine the reliability of familiarity ratings. The correlation between the word familiarities of the two sets was extremely high (r = .958, N = 10,515). It is suggested that familiarity rating, at least for ordinary words found in a dictionary, is very reliable and not greatly affected by differences in years and places.

Fundamental frequency of infants' and parents' utterances in longitudinal recordings.

The fundamental frequencies (F0) of daily life utterances of Japanese infants and their parents from the infant's birth until about 5 years of age were longitudinally analyzed. The analysis revealed that an infant's F0 mean decreases as a function of month of age. It also showed that within- and between-utterance variability in infant F0 is different before and after the onset of two-word utterances, probably reflecting the difference between linguistic and nonlinguistic utterances. Parents' F0 mean is high in infant-directed speech (IDS) before the onset of two-word utterances, but it gradually decreases and reaches almost the same value as in adult-directed speech after the onset of two-word utterances. The between-utterance variability of parents' F0 in IDS is large before the onset of two-word utterances and it subsequently becomes smaller. It is suggested that these changes of parents' F0 are closely related to the feasibility of communication between infants and parents.

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.

Variables affecting naming latency for Japanese Kanji: a re-analysis of Yamazaki, et al. (1997).

Yamazaki, Ellis, Morrison, and Lambon Ralph in 1997 demonstrated that written and spoken age-of-acquisitions had a stronger effect on the naming latency of single Kanji words than any other variable including familiarity. The present study was designed to reanalyze Yamazaki, et al.'s data, using the ratings of written and spoken age-of-acquisitions and visual and auditory familiarities taken from the NTT lexical database. This analysis showed that visual familiarity exerted a stronger independent effect on naming latency than two types of age-of-acquisitions.