本文根據我們前往金門田野調查所得的材料，討論金門閩南語中 tа2 這個語法成分。在金門閩南語，tа2 主要是在[NP1-tа2-NP2-VP]這 類結構中作為引介名詞組成分（NP2）的介詞。從語義角色來看，tа2 所引介的名詞組成分，其內涵包括：來源者（source）、標的者（goal）、 受益者（beneficiary）、受損者（malefactive）和受事成分（patient）。 本文的工作包括：1.根據田野資料，全面地描寫金門閩南語tа2 的語 法功能；2.利用不同性質的早期閩南語文獻以及音韻規則對應，說明 金門閩南語tа2 的語源；3.探索金門閩南語tа2 所經歷的語法化過程， 並與漢語語法史進行比較，說明兩者的異同。 本文的結論是：第一、金門閩南語的ta2 來自「同」，這可以從 早期閩南語文獻及音韻規則對應得到證明；換言之，金門閩南語的ta2 與臺灣閩南語ka6 並不同源，也不是方言變體。第二、本文檢討過去 學者根據臺灣閩南語的現象所提出的語法化假設。我們認為，就類型 學而言，閩南語是區分協同行為者介詞（即與同介詞，commitative preposition）與非協同行為者介詞（non-commitative preposition）的漢語方言，協同行為者介詞並不直接演變為受事／來源標誌及動前賓語標誌。相對地，閩南語中的受事成分介詞是從「共有義」動詞語法化而來，與來自「聚合義」的協同行為者介詞在現階段仍然對立，是比較保守的類型。

This article, based on my first-hand field notes, investigates grammatical functions of the preposition ta2 in the Southern Min spoken in Kinmen County. The major syntactic function of the preposition ta2 is to introduce a noun phrase (i.e. the NP2) in the structure [NP1- ta11-NP2-VP]. Semantically speaking, ta2 codes five semantic roles, those of source, goal, beneficiary, malefactive and patient. This article observes that ta2 functionally parallels the preposition ka6 in Taiwan Southern Min. Therefore, the relation between ta2 and ka6 deserves a unified explanation. It is essential to clarify whether the two prepositions (i) are phonological variants of a cognate, or (ii) descendants of different proto forms. My effort to clarify this issue is divided into three parts. First, I thoroughly describe the grammatical functions of ta2 in modern Southern Min. Second, I probe into the diachronic origin of ta2 in early documents with corresponding phonological rules. Third, I account for the relations between the grammaticalization of ta2 and language change in the historical grammar of Mandarin. This article obtains two main findings. First, the preposition ta2 originates from the word tong (同). Data from early documents and phonological rules afford abundant evidence to substantiate this claim. That is to say, ta2 is neither cognate with ka6 (共gòng) nor a dialectal variant of ka6. Second, Southern Min, from a typological view, is a language that exhibits the distinction between commitative prepositions and non-commitative prepositions. My analysis differs from the previously hypothesized path of grammaticalization: commitative preposition > marker of patient and source > preverbal object marker. The main reason is that the commitative preposition does not shift to the marker of patient/source or even to the preverbal object marker. I claim that preposition phrases that take patient arguments are derived from the grammaticalization of verbs that denote the sense of sharing. By contrast, commitative prepositions are derived from the verb denoting the sense of gathering. In other words, these two types of prepositions, which originated from different verbal meanings, still remain synchronically distinct categories in Modern Southern Min.