吃音者のワーキングメモリ(WM)容量とシャドーイング潜時の関係について検討した。発達性吃音症であると判断した吃音者21例(男性18名、女性3名、18〜38歳)と非吃音者15例(男性10名、女性5名、19〜37歳)を対象とした。分布範囲は大きく重なっているが、統計的には吃音者群のリーディングスパンテスト(RST)得点が非吃音者群より有意に低かった。吃音者の追唱潜時が非吃音者より有意に短かった。非吃音者群の最短追唱潜時より短い潜時の者は吃音者群に4例いた。1000ms以上の潜時の者は非吃音者群に6例いたが、吃音者群は0例であった。RST得点と追唱潜時の関係において、散布図では吃音者群は比較的連続的に分布し、非吃音者群とは殆ど重なりがなかった。非吃音者群内で短い追唱潜時を示した参加者を一つの群として注目すると、同様なRST得点を示した吃音者の追唱潜時はこの群より長く、同様な追唱潜時を示した吃音者のRST得点が低かった。RST得点と追唱潜時の相関係数を求めたところ、吃音者群では有意な正の相関があるのに対し、非吃音者群では有意な負の相関を認めた。

The present study investigated the relationship between working memory capacity (WMC) and shadowing latency in 21 people who stutter (PWS) and 15 people who do not stutter (PWNS). WMC was measured using the Reading Span Test (RST). The mean RST score of the PWS group was significantly lower than that of the PWNS group. The PWS group also showed significantly shorter shadowing latency than the PWNS group. In terms of the relationship between WMC and shadowing latency, the PWS group had a significant positive correlation, whereas the PWNS group showed a significant negative correlation. These results suggest that PWS and PWNS employ different processing strategies in verbal working memory and shadowing tasks.

成人吃音者16名(男性13名、女性3名:年齢18〜38歳)を対象に、吃音への短期シャドーイング訓練の効果について検証した。音読用の3つの課題文、シャドーイング用の4種類の課題文を用意し、1回音読した後に4種類の課題文を1〜3回ずつシャドーイングする訓練を行った。音読課題で吃音頻度が高かった8名はシャドーイング中に吃音頻度が大きく減少し、症状の持続時間が短縮した。また、シャドーイング直後の音読はシャドーイング前と比較して吃音の頻度が減少し、後効果が認められた。さらに、自由記述の感想・意見を分析した結果、シャドーイングにより流暢な発話を実感できたことにより、心理面にポジティブな影響を与えていた。

吃音のある成人の日常生活上における困難の実態について面接調査を実施した。幼児期あるいは学童期から吃音を経験している成人10例(男8名、女2名、平均28.8歳)を対象とし、学生5例、職業人5例であった。10例の叙述逐語録は、合計2310081文字(平均23108±8493文字)であった。概念生成ICFのモデルにおける四つのカテゴリー(心身機能・身体構造、活動・参加、個人因子、環境因子)に対し生成されたサブカテゴリーにおいて、「心身機能・身体構造」のカテゴリーの下には2種のサブカテゴリー、「活動・参加」のカテゴリーの下には6種のサブカテゴリーと31種の概念、「個人因子」のカテゴリーの下には7種のサブカテゴリーと47種の概念、「環境因子」のカテゴリーの下には3種のサブカテゴリーと23種の概念が生成された。合計で108の概念が抽出された。

The present study investigated the short-term effects of speech shadowing training in 16 people who stutter (PWS). Speech shadowing is a task in which subjects listen to a spoken passage and repeat it with the shortest possible delay. In a subgroup of 8 PWS whose reading contained more than 3% of stuttered phrases before shadowing, the frequency of stuttering, especially blocking, and the mean duration of stuttering symptoms decreased during shadowing. They also produced significantly fewer dysfluencies in the reading-aloud task after shadowing than in the initial reading task, regardless of use of the same or different reading materials. The other 8 PWS with fewer than 3% dysfluencies before shadowing showed no significant change in stuttering frequency during or after shadowing. Thus, speech shadowing has a short-term aftereffect of reducing the frequency of stuttering, as well as possible usefulness by giving a chance to those with frequent symptoms to experience fluent speech during training. Analysis of the participants' free comments after the training based on the KJ (card sorting) method showed that they felt their speech was more fluent during shadowing than usual, and that they were looking forward to more shadowing training.

Speech shadowing is a dual-task paradigm that could reveal certain features of speech processing, where the shadowing latency between the onsets of heard and reproduced speech has often been a key investigation tool. The present study investigated the shadowing latencies in native Japanese adults who do (AWS) and do not stutter (AWNS), with relevant analysis of speech errors. Fifteen AWS and fourteen AWNS participated in the study. They were required to shadow two meaningful Japanese passages of approximately 1.4 min. Fifty phrase onsets were chosen for measuring shadowing latencies. The resultant latencies were longer than previously reported for English in both groups, which most likely reflects the larger mean syllable numbers per word of Japanese than of English. The AWS group had a significantly shorter latency than the AWNS. Besides, it was significantly more error-prone than the AWNS. The eleven AWS whose latency was more than 500 ms showed a significant negative correlation (trade off) between speech errors and latencies, which was not the case with the AWNS group. Those results imply that only the AWS may have hit the limit of their working memory capacity during shadowing. Thus the shadowing paradigm brought new insights into speech processing and stuttering.

The present study reports native speakers' impressions of JFL learners' utterances before and after shadowing/repeating training. Evaluation was also done for prosodically modified synthesized stimuli in order to examine the crucial prosodic cues. The results suggest that both durational patterns and pitch patterns are important for the utterances to be heard as natural Japanese, but durational patterns may be more important. Moreover, shadowing training appears to improve mora-timed rhythm. The results of the present study could provide useful suggestions for developing pronunciation training for Japanese pronunciation and speech education.

We conducted a longitudinal study on the effectiveness of shadowing training for Chinese and Mongolian learners of Japanese. The purpose of the present study was to clarify (1) the effect of longitudinal shadowing training for realization of pitch accent, and (2) to discuss if the difference of effectiveness depends on the learners' proficiency level as well as their first language. 15 Japanese as a foreign language (JFL) learners participated in this study. They are divided into two groups according to their level of Japanese proficiency. Each group was instructed to shadow a dialog ten times without seeing a script for three sessions over a seven week period. The results showed that speech rate and accuracy of pitch accent rose significantly after seven weeks in both groups, but each group was different in the ways of improvement.

In this study, the effect of shadowing and reading/repeating training on learners of Japanese was examined. The purpose of the present study was to clarify, (1) phonetic characteristics of learners' pronunciation during/after shadowing and repeating, (2) if the effect of shadowing training is different depending on the learners' mother tongue, and (3) what kind of phonetic characteristic are effectively improved by shadowing training. The results of experiments with Mongolian and Chinese learners of Japanese showed: a) both shadowing and reading/repeating training helped increase speech rate, b) accuracy rate of accent pattern rose during shadowing training differently in Mongolian and Chinese groups and c) the effect of shadowing training is more effective for acquiring prosodic features.