「X+子」的詞彙如「父子、公子、獅子」，內部關係涵蓋詞組、複合詞、附加詞三種樣貌，反應雙音化趨勢下衍生出的詞彙化與語法化過程，「X＋子」由句法結構的詞組融合為詞法結構的複合詞，稱為「詞彙化」，「X＋子」再由複合詞虛化為附加詞的過程，稱為「語法化」。句法到詞法、詞根虛化為詞綴都是一個連續統的漸變過程，在詞彙化進程中，董秀芳(2002b)提出詞化程度的級差，石毓智(2002)提出融合程度說，本文觀察「X＋子」在歷時發展中表現出3個詞化程度的差別，依序是：構詞成分不能換序、構詞成分語義細微差異消失，以及意義上發生換喻或隱喻的引申；「類前／後綴」的概念，顯示詞根虛化為詞綴的連續性，本文觀察類詞綴「子」作為過渡階段主要在六朝以前，語義大部分虛化仍隱含有小的意味，唐代以後「子」完成了虛化。其次，一般學者將後綴「子」視為名物化標記，本文根據學者所提出的25個例子，考察歷史語料只得出6 個例子可證明後綴「子」具有為名物化功能，其餘多數「X」應是雙音化趨勢下純粹加「子」綴的現象。

X+子 may be a phrase, compound or root+suffix, which reflects the results of lexicalization or even grammaticalization during the process of disyllabification. The compounding process of X+子 is called lexicalization, while 子 further developed into a suffix is grammaticalization. From diachronic perspective, there are two findings in this paper: (1) the variety of X+子shows different degrees of lexicalization, and their characteristics are: a) the idiomatization, b) the fusion of lexical meanings, and c) semantic change caused by metaphor or metonymy; (2) the concept of semi-affix shows a continuous and gradual change of X+子 from a root of a compound into a suffix during the six dynasties. One of the functions of suffix 子 is a nominalizer; however, after checking the twenty five examples in the historical documents, only six of them are nominalized by 子, while the others are resulted from disyllabification.