以追蹤性研究探討華語嬰兒喃語發展、嬰兒導向式語言，與2歲語言表達能力

本研究使用LENA家庭式錄音追蹤分析7、9、11個月嬰兒的發聲量及典型喃語之表現，探討自然互動中成人使用嬰兒導向式語言對嬰幼兒語言表達能力之影響，以及嬰兒的語音表現和2歲語言表達能力之關聯性。本研究含七位嬰幼兒受試者，分別於7、9、11個月大時進行每個月4至6次的全天候家庭錄音。研究結果顯示嬰兒典型喃語比例隨月齡增加，11個月顯著大於7個月，意味嬰兒出現語音形式的進展。成人語言刺激量方面，成人使用的嬰兒導向式語言量與嬰兒發聲量無顯著關聯性，但與嬰兒典型喃語比例呈顯著負相關。雖成人嬰兒導向式語言未直接提升嬰兒典型喃語比例，但若與兩歲語言表達能力比較，本研究發現家庭環境中成人所使用的嬰兒導向式語言量及嬰兒時期的典型喃語比例，皆與未來兩歲時的語言表達能力呈顯著正相關，即嬰兒環境中的語言刺激量和嬰兒自身的語音能力，皆是影響兩歲語言表達能力的重要因素。透過追蹤性研究，本研究證實華語嬰兒的典型喃語比例會隨月齡增長，且與日後幼兒語言表達能力具重要相關性。

This study used LENA home recordings to collect infant vocalizations, and to explore the development of canonical babbling ratios (CBRs), the effects of infant-directed speech on infants’ prelinguistic development, and the relations between infants’ canonical babbling and their expressive language at 2 years old. The study included seven mother-infant dyads. All data collections were completed using LENA recorders conducted at home environments when subjects were at 7, 9, and 11 months. The recordings were selected and coded manually to obtain a representative sample of the child’s CBRs and caregiver’s infant-directed speech at each age. When the child reached 2 years old, we used two standardized assessment tools (i.e. MCDI-T and CLST) to assess the child’s vocabulary size and expressive language. Results showed that the mean of children’s canonical babbling ratios increases significantly from 7 months to 11 months. The amount of infant-directed speech that infants received during infancy is negatively correlated with CBRs, but positively correlated with their expressive language scores at 2 years. More importantly, CBRs in infancy is significantly correlated with infants’ vocabulary size and expressive language at 2 years old, showing how infants’ canonical babbling lay foundation for their later acquisition of vocabulary and morpho-syntactic abilities. This study not only sheds light on the importance of canonical babbling as one of the earliest red flags of language delay and language disorder, but also provides crucial crosslinguistic evidence about infants’ prelinguistic development in the Mandarin-speaking population.