本研究考察了現代越南語中進行體標記đang的語法化過程。Đang來源於漢語“當”（dāng，“在”義），它後面經常跟隨著名詞、代詞或名詞短語修飾的“時”（“時間”義）。例如，“當[A]之時”，其中A是名詞、代詞或名詞短語（Pulleyblank 1995）。在15世紀出版的漢喃對譯文本中，漢語“當”有5處譯為“當”，有1處譯為“侯”，有4處譯為“合”。另一方面，在17世紀的越南拉丁文文本中，該詞彙經常出現在從屬（附加）子句中。例如，（a）đang NP（時間短語）；（b）đang khi NP+VP；（c）khi（NP）đang VP。通過與越南漢文中“當”的用法比較可知，這些模式意味著一個發展順序：（Ch）當+NP+VP+（SUB）+NPtemp >（Ch）NP+當+VP+（SUB）+NPtemp >（V）*NP+Dang+VP+khi >（V）khi+NP+Dang+VP。之後，"đang+VP"被重新分析，產生了進行體標記đang。

This study considers the grammaticalization process that produced the progressive marker đang in modern Vietnamese. The word đang originates from the Chinese 當 dāng, which means 'be at.' Frequently it is followed by 時 'time' modified by a noun, pronoun or noun phrase, e.g., 當 [A] 之時 'at the time of/when [A],' where A is a noun, pronoun, or noun phrase (Pulleyblank 1995). In Sino-Vietnamese Nôm texts published in the 15th century, Chinese dāng is translated as 當 đang/đương in five cases, as 侯 hầu 'be about to' in one case, and as 合 hợp 'right' in four cases. Meanwhile, in the Romanized texts of the 17th century, the element very often occurs in subordinate (adjunct) clauses, e.g., (a) đang NP (Time phrase); (b) đang khi NP+VP; and (c) khi (NP) đang VP. These patterns, compared with the usages of 當 in literary Sinitic in Vietnam, imply a sequence of developments: (Ch) 當 +NP+VP+(SUB)+NP_(temp) > (Ch) NP+ 當 +VP+(SUB)+NP_(temp) > (V) *NP+đang+VP+khi > (V) khi+NP+đang+VP. After that, the unit 'đang+VP' was reanalyzed to give rise to the progressive marker đang.