華語學齡發展性語言障礙兒童的聲調聽知覺處理型態之驗證

發展性語言障礙（Developmental Language Disorder, DLD）兒童在聽知覺處理能力有困難，研究發現華語兒童的聲調聽知覺處理能力和語言學習能力最為相關，華語聲調除了含基礎聽覺聲學線索，還如同語音具有區辨語意的功能。本研究旨在探討華語學齡DLD兒童的聲調聽知覺處理表現與可能的缺陷機制—為語音特定缺陷抑或一般性聽覺處理缺陷。研究參與者為26名平均年齡9.5歲的DLD兒童，26名年齡與性別匹配的典型發展（typical development, TD）兒童，兩組兒童經過「兒童基本資料與發展調查表」、聽力篩檢、標準化語言及非語文認知測驗的篩選，確認進入本研究之分組，接著，根據兩組兒童在單音節字詞聲調聽知覺測驗的表現，以及操弄刺激音類型、刺激音時長之基頻走勢區別測驗的表現進行分析。結果顯示，DLD組在聽知覺處理聲學線索較複雜的二聲、三聲有困難，並且在各項聲調聽知覺處理能力都顯著較TD組不佳；基頻走勢區別測驗中，DLD組在字調（語音）、音調（非語音）區別表現皆顯著較TD組差，兩組兒童的表現都隨刺激音時長增加而顯著提升，然而DLD組在任何時長的表現皆顯著較TD組不佳；全體兒童在各聲調聽知覺表現之間都有顯著相關，相較於非語音，語音聲調聽知覺表現與接收性語言測驗表現的相關性更顯著，且字調區別能力最能解釋語言理解能力的變異量。經檢驗結果得知，華語學齡DLD兒童的聲調聽知覺處理困難包含了一般性聽覺處理缺陷的成分，然而處理困難的關鍵在「時頻譜」而非「時間」線索，儘管如此，聲調的時頻譜線索搭載在語音之上，可能對語言理解能力有較大程度的貢獻。本研究結論建議，能對華語DLD兒童進行聲調聽知覺處理或聲調覺識相關的介入，並且在聲調訓練或一般語言輸入時，使用放慢語速以完整話語中聲調基頻走勢線索的聲學強調技巧，應能有助於促進DLD兒童的語言理解。

It was acknowledged that Children with Developmental Language Disorder (DLD) have difficulties in auditory perception and processing. For Mandarin children, the lexical tone perception and processing is most closely related to language learning. Mandarin tones not only contain auditory acoustic cues but function as phonemes to distinguish meanings. The current study aimed to examine the performance and probably deficit mechanisms of tone auditory perception and processing in Mandarin school-aged children with DLD—whether the deficit is speech-specific or general auditory processing. Participants were 26 children with DLD, averaging 9.5 years of age, and 26 age- and gender-matched children exhibit typical development (TD). Each child was confirmed to meet the selection criteria using a questionnaire for child development, hearing screening, standardized language, and nonverbal cognitive tests. The performances were measured using the Lexical Tone Test Battery and the self-designed fundamental frequency (F0) trajectory discrimination test, which manipulated stimulus type and duration. Results showed that the DLD group had more difficulty processing high-rising tone (T2) and low-dipping tone (T3), characterized by relatively complex F0 properties. Moreover, the DLD group performed significantly worse than the TD group in all Mandarin tone auditory perception and processing tasks. In F0 trajectory discrimination test, the DLD group also performed significantly worse than the TD group in both lexical tone (speech) and pitch (nonspeech) discrimination subtests. Additionally, both groups’ performance improved significantly with increased stimulus duration. However, the DLD group performed significantly worse than the TD group at all durations. For all children, there were significant correlations among various Mandarin tone auditory perception and processing tasks, and the performance on speech tasks was more significantly related to receptive language performance compared to the nonspeech task. Lexical tone discrimination ability was also the best predictor of language comprehension ability. The findings suggest that Mandarin tone auditory and perception difficulties in Mandarin school-aged children with DLD can be attributed to general auditory processing deficits, however, the critical factor lies in “spectrogram” rather than “temporal” cue. Nonetheless, the spectrogram cues of Mandarin tones, which are embedded in speech, might contribute more to the language comprehension ability in children with DLD.It is recommended to provide interventions focused on Mandarin tone auditory perception and processing, and lexical tone awareness for children with DLD. During the training or general input, using acoustic enhancement techniques, such as slowing the speech rate to fully present the pitch contour cues in speech, might benefit the language comprehension of children with DLD.