汉语句末助词出现在汉语普通话的语句末尾，是功能词类。它们的意义比较空灵，不包含具体的所指内容，却能够表达说话者对语句内容的不同态度。同时，相同的汉语句末助词可以出现在不同的上下文中，表达各种含义。在汉语句法研究中，句末助词的句法位置位于CP投射下。通过对汉语句末助词的早期习得研究，我们可以了解儿童对汉语功能词类的习得，并探索汉语CP结构在早期儿童语言中的发展情况。本文研究了汉语儿童对句末助词“呢”、“吧”、“吗”和“嘛”的早期习得，旨在通过研究句末助词在儿童语言早期的发展模式、儿童如何习得句末助词的丰富特性、以及成人语言输入对儿童习得所产生的影响，从跨语言的角度为功能词类的习得研究做出贡献。本文所使用的语料来自于BJCELA语料库中对四名母语为汉语儿童的跟踪研究。通过分析这四名儿童从10个月到24个月之间产出的自然语料，我们发现儿童在两岁前已经产出“呢”、“吧”、“吗”和“嘛”这四个句末助词，并且能够在各种上下文中使用，表达不同意义。同时，对成人输入与儿童产出的深入分析以及半对数回归分析结果证明，成人输入与儿童句末助词的产出在统计上没有显著相关性，但是儿童使用的部分句末助词与成人的输入仍具有相似性。研究结果表明，作为功能词类，句末助词在儿童语言发展的早期已经得到较为丰富的使用，并不存在缺失现象。因此，功能词类存在于儿童语言习得的初始阶段。而成人语言输入对儿童习得汉语句末助词虽不具有决定性作用，但仍然为儿童获取触发性数据提供了丰富的来源。
Sentence Final Particles (SFPs) in Mandarin Chinese constitute a functional category that typically occurs in the sentence final position. On one hand, they bear no referential content, but contribute rich information concerning the speaker’s attitude to the proposition. On the other hand, the same particle can occur in many contexts with subtle differences in meaning. As a functional category, the use of SFPs can reveal whether child grammar is essentially different from that of adult. Since SFPs are categorized into the CP domain, they serve as a window to explore the CP structure of Mandarin in early grammatical development.Given such a theoretical background, the present study will explore how Mandarin-speaking children use SFPs in the initial state and whether adult input plays an important role in language acquisition. To address these questions, we have drawn on the production data of four Mandarin-speaking children from the BJCELA corpus and analyzed the developmental patterns and children’s use of SFPs NE, BA, MA1, and MA2 before age two. We believe that our study will not only enhance our understanding of acquisition of this particular category in child Mandarin, but also contribute to the long-standing debate over the initial state of functional categories in child grammar.The data show that children are able to productively use SFPs NE, BA, MA1, and MA2 before age two in various sentence types including declaratives, imperatives and interrogatives to express different meanings. Results further show that there is no statistically significant correlation between adult input and child production, but children’s production of some SFPs are very similar to that of adults. Even though adult input does not play a decisive role, it is still necessary for children to pick up the triggering data in the specific language input. Findings of the present study support the claim that functional categories are available to children in the initial state.
