Abstract
摘要:嬰兒語音知覺能力在六到十二個月大之間產生劇烈的變化。在六到八個月大之間能夠區辨母語和外語中的輔音差異,也就是顯現「語言共通」的知覺處理特性。而在十到十二個月大時,嬰兒對於母語輔音的差異越來越敏感,但是同時也降低對於外語輔音差異的敏感度,也就是顯示「語言特定」的知覺歷程。相對於輔音知覺研究,關於嬰兒期聲調知覺的研究非常稀少。不過,近幾年的研究顯示聲調知覺敏感度也在六到十二個月大之間產生變化。輔音知覺研究顯示,「嬰兒導向式語言(infant-directed speech,IDS)」這種常見的親子互動形式,是促進語音知覺發展的重要機制。明顯的抑揚頓挫,則是嬰兒導向式語言情緒語調(emotional prosody)的主要特徵。如果嬰兒導向式語言有助於嬰兒學習聲調,是否其中的情緒語調也會影響嬰兒聲調敏感度的發展?除了嬰兒導向式語言,「分配式學習(distributional learning)」也是輔音知覺發展的學習機制。是否這項學習機制,也解釋情緒語調對聲調知覺發展的影響?此外,聲調區辨的敏感度在學齡前及國小學童中依然成長。是否表示這個時期的知覺敏感度變化,反映了聲調表徵分類化程度的成長?將規劃一系列的三個實驗來探索這些議題。實驗一測試情緒語調對嬰兒聲調敏感度發展的影響。七和十一個月大嬰兒將聆聽兩類情緒語調(高興和中性)中的聲調,並區辨聲學相似度有別的兩組聲調對比:「二聲vs. 三聲」和「二聲 vs. 四聲」。如果情緒語調影響聲調區辨,預期高興語調中的知覺表現將優於中性語調的情況。此外,十一個月大嬰兒的區辨敏感度可能優於七個月大嬰兒,以顯示聲調知覺的發展趨勢。但是,情緒語調的影響可能受到聲學相似度影響。實驗二進一步探索情緒語調效果,是否經由分配式學習來影響聲調敏感度的發展趨勢。七和十一個月大嬰兒將區辨聲調對比,而聲調出現於嬰兒導向式語言中較常出現的高興語調,及較少出現的悲傷語調兩種情況當中。如果高興語調情況下的聲調區辨表現優於悲傷語調,將支持分配式學習影響語言知覺發展的假設。實驗三將以聲學上單一向度連續變化的聲調「連續體(continuum)」,測試五到七歲兒童的聲調分類程度。而且,這些連續體也將呈現於高興和悲傷兩種情緒語調當中,並以聲調辨識和區辨作業檢視兒童的聲調分類程度。相對於年幼兒童,預期年紀較大兒童出現較陡的聲調辨識曲線和較精確的區辨反應,以反應聲調分類程度隨年紀而出現的轉變。另外,聲調分類程度可能因情緒語調而變化,以顯示情緒語調對聲調分類的影響。研究的結果除了瞭解情緒語調如何影響聲調的學習過程之外,由於情緒語調是嬰兒導向語言的主要特徵,研究結果也將顯示嬰兒如何和環境互動以學習語言。而經由探索情緒語調對兒童期的聲調分類能力發展,也有助於理解從嬰兒期到兒童期,聲調知覺發展從渾沌不明到範疇清晰的發展過程。
Abstract: Perceptual sensitivity of consonants and vowels undergo rapidly changes during the firstyear of life. Infants begin life with a universal capacity to distinguish phonemes of nativeand foreign languages. The effects of native language experience on speech perceptiondevelopment are evident with the reduced sensitivity to discriminate non-native phonemesand improving sensitivity to discriminate native phonemes between 6 and 12 months of age.However, only few studies explored the lexical tone perception development in infancy andit not very clear what learning mechanisms would account for the developmental changes oflexical tone perception development. Infant-directed speech (IDS) is a universal featurewhen parents interact with their infants and it plays key role in facilitating phoneticperception development. Exaggerated emotional prosody characterizes IDS. Wouldemotional prosody affect the lexical tone perception development in infancy andcategorization of lexical tones in childhood? In addition, would distributional learningaccount for the effects of emotional prosody on lexical tone perception development? Aseries of three experiments are designed to explore these questions.First goal of this study is to assess whether emotional prosody has any impacts on theperceptual sensitivity to lexical tone contrasts in 7- and 11-month-old Mandarin-learninginfants. In Experiment 1, infants will be tested with lexical tone contrasts varying in bothacoustic similarity (i.e., Tone 2 vs. 3 and Tone 2 vs. 4) and emotional prosody (i.e., happyand neutral prosody). It is anticipated that infants would be more sensitive to the lexical tonedifferences in happy prosody than neutral prosody to demonstrate the facilitation effect ofpositive prosody in speech perception.The second goal of this study is to explore whether distributional learning mechanism ofspeech perception might account for the positive effect of happy prosody in lexical toneperception development. In Experiment 2, Mandarin-learning infants will be tested with twotypes of emotional prosody, happy and sad prosody, that varies in the occurrence frequency ofIDS. To demonstrate the facilitation role of emotional prosody, infants are anticipated to bemore sensitive to the lexical tone difference in happy prosody than in sad prosody. Becausedistributional frequency difference between happy and sad prosody would account for theperformance difference between types of emotional prosody, these results would suggest thatthat distributional learning facilitate infants learning lexical tones.Finally, the third goal of this study is to explore the effects of emotional prosody onlexical tone categorization in 5- to 7-year-old children. In Experiment 3, children will betested with two sets of lexical tone continuum, one set of lexical tones is expressed withhappy prosody and other set is expressed with sad prosody. Children will have to identifylexical tones of speech continuum and distinguish lexical tones along the speech continuum. Itis anticipated that degree of lexical tone categorization would vary with emotional prosodyand provide support to the hypothesis that emotional prosody affects the categorization oflexical tones in childhood. .
Keyword(s)
情緒語調
聲調知覺
語音知覺發展
聲調區辨
嬰兒
兒童
聲調分類
lexical tone perception
learning mechanism of speech perception
infancy
childhood
emotional prosody
infant-directed speech
categorization of lexical tones