“吗”是普通话中常见的疑问语气词，在言语活动中有时会与另外一个非疑问语气词“嘛”产生混淆。通过对已有研究进行梳理可以发现，“吗”“嘛”字形上的混淆反映了语气信息的误解。语音形式、语言使用都会影响语气信息的表达和理解，但具体的影响的方式尚不明晰。因此，本研究从“吗”“嘛”混淆现象入手，综合采用声学分析、听感实验、语料库研究和言语行为分析，讨论了[ma]的目标音高范畴、语言使用对[ma]目标音高范畴形成的影响以及“吗”“嘛”混淆的本质三个问题。

    第一，通过对产出实验得到的实验句进行声学分析，考察不同语气[ma]字句的句调表现，并与陈述语调和疑问语调进行对比，指出[ma]字句的语气声学相关量是其句调中句末语气词[ma]的目标音高。进一步通过辨认实验和区分实验，发现[ma]字句语气听感线索也是其句末语气词[ma]的目标音高。对比产出实验和听感实验结果，结合语料库研究结论，确定了不同语气句末语气词[ma]的目标音高范畴，明确了音高范畴之间存在交叉，讨论了祈使语气词“嘛”和陈述语气词“嘛”目标音高听感空间上线的差异。

    第二，通过言语行为分析，考察了[ma]字句语气和交际意图之间的对应关系，明确了“吗”字句也可以用来表示请求，在交际意图方面与“嘛”字祈使句有所交叉，与“嘛”字陈述句界限分明。这种交际意图交叉情况的差异，是祈使语气词“嘛”和陈述语气词“嘛”目标音高空间上线不一致的原因。

    第三，综合以上结论，提出[ma]字句在语言理论层面上包含句法表现、语音形式和交际意图三个层级的交叉，这三个层级的交叉是言语交际层面上“吗”“嘛”混淆现象产生的原因。指出“吗”“嘛”混淆现象的本质是，听话人无法依据句末语气词[ma]的目标音高解读[ma]字句表达的语气信息。

     Firstly, through the acoustic analysis, this study finds that the acoustic correlation of the mood information of [ma] sentences is the target pitch of [ma]. Further, through the identification experiment and the distinguishing experiment, this study clarifies that the auditory clue of the mood information of [ma] sentences is also the target pitch of [ma].
    Secondly, by comparing the results of output experiment and auditory experiment, this study finds out the target pitch category of different modal particle [ma]. 
    Thirdly, through the acoustic analysis of the [ma] sentences in the corpus, it is found that the target pitch space of [ma] with different moods exists crossover. Through the analysis of speech act, this study proposes that [ma] sentences contain three levels of crossover at the aspect of language, which are the causes of the confusion of "吗" and "嘛". Finally, based on the above conclusions, it is pointed out that the essence of the confusion of "吗" and "嘛" is that the listener cannot understand the mood information conveyed by the target pitch of modal particles.