Abstract：
The quality of speech input influences the efficiency of L1 and L2 acquisition. This study examined modifications in infant-directed speech (IDS) and foreigner-directed speech (FDS) in Standard Mandarin-a tonal language-and explored how IDS and FDS features were manifested in disyllabic words and a longer discourse. The study aimed to determine which characteristics of IDS and FDS were enhanced in comparison with adult-directed speech (ADS), and how IDS and FDS differed when measured in a common set of acoustic parameters. For words, it was found that tone-bearing vowel duration, mean and range of fundamental frequency (F0), and the lexical tone contours were enhanced in IDS and FDS relative to ADS, except for the dipping Tone 3 that exhibited an unexpected lowering in FDS, but no modification in IDS when compared with ADS. For the discourse, different aspects of temporal and F0 enhancements were emphasized in IDS and FDS: the mean F0 was higher in IDS whereas the total discourse duration was greater in FDS. These findings add to the growing literature on L1 and L2 speech input characteristics and their role in language acquisition.
摘要：
语音输入的质量影响L1和L2采集的效率。这项研究研究了标准普通话（一种音调语言）中婴儿定向语音（IDS）和外国人定向语音（FDS）的修改，并探讨了IDS和FDS特征如何在双音节单词和更长的话语中表现出来。该研究旨在确定与成人导向语音（ADS）相比，IDS和FDS的哪些特征得到了增强，以及在一组常见的声学参数中测量时，IDS和FDS如何不同。Forwords,发现音调元音持续时间，基频的平均值和范围(F0)，IDS和FDS中的词汇音调轮廓相对于ADS得到了增强，除了浸渍音3表现出意外的FDS下降，但与ADS相比，IDS中没有任何修改。对于话语，IDS和FDS强调了时间和F0增强的不同方面：IDS中的平均F0较高，而FDS中的总话语持续时间较长。这些发现增加了有关L1和L2语音输入特征及其在语言习得中的作用的文献。
