「說」在中文具有多種語言功能，它可以是基本動詞（如1），或是補語標記（如2），甚或是句尾助詞（如3）：
(1) 說 長道短。
(2) 有些人覺得 說 他很不盡情理。
(3) 這整件事很好笑 說。
基於 Hopper (1987) 語法化緣於語用之信念，我將在本文中以Traugott (1989) 之語法化理論檢視中文「說」 的不同用法。嘗試經由其言談功能及語意變遷，提出心理動詞 (如相信、覺得、希望)後所接的「說」反映出Vygotsky (1962) 所談的思想具備了與語言類似之特點的看法。同時，我也認為語料顯示主要動詞後的「說」是否出現，標示的是不盡相同的言談功能。本論文將以「主觀化」理論解釋「說」由動詞，而補語標記，而表態度語尾助詞的發展。這樣的研究應可結合當今語用學及認知語言學兩者對於語意的重要見解。

SHUO in Mandarin Chinese codes various linguistic functions, ranging from a main verb “to say,” as in (1), to a complementizer introducing sentential complements embedded under the matrix verbs, as in (2), to even a sentential final particle, as in (3):
(1) 說 (SHUO)長道短。
(2) 有些人覺得說 (SHUO) 他很不盡情理。
(3) 這整件事很好笑說 (SHUO)。
Assuming that dynamic process of language gives rise to grammaticalization (Hopper 1987), I will follow closely in this paper Traugott’s claim on grammaticalization (Traugott 1989) so as to investigate the various uses of SHUO. Via the study of its discourse function in relation to its semantic change, I conclude that the occurrence of SHUO after mental verbs such as xiangxin, juede, or xiwang, demonstrates the homogeneity of speech and thought (Vygotsky 1962), and the non-obligatory presence of SHUO after the matrix verbs marks different discourse functions of the utterances. I will argue that the process known as subjectification should take full responsibility for the development of the shift of SHUO as a main verb, to a complementizer, and finally to an epistemic particle. It is hoped that this study may synthesize important insights concerning pragmatic phenomena with current developments in cognitive linguistics concerning the study of linguistic meaning.