一般認為吳語是「江蘇浙江當中並定羣等母帶音，或不帶音而有帶音氣流的語言」，而閩語則有古「端知」不分的特徵。最近發現有些吳語方言的白話層也有「端知」不分的現象，本文對這個現象提出一個解釋，並增加一點歷史上的證據。結論是吳語的底層具有閩語的特徵，可能南北朝的「吳語」就是現在閩語的前身，而當時的北方語言則是現在吳語的祖先。

Generally speaking, we accept Y. R. Chao's (1928: 88) definition of the Wu dialects spoken in the Chiang-su and Che-chiang provinces, in which the ancient sonants ping 並、ting 定、ch'un 羣、ch'uang 床, etc, remain as sonants or apparent sonants.  We also agree that the Min dialects preserve the archaic feature of a lack of distinction between dentals (tuan 端) and supradentals (chih 知).  Recently, we noticed that some of the Wu dialects also preserve this feature, I would like to provide an explanation in this paper.

Comparing the literary and colloquial readings in the Wu dialects, we have to admit that there existed a colloquial Min substratum of early stage in the Wu dialects.  This substratum represents a residue of the "Wu Yu" of the Southern Dynasties, which is probably the ancestor language of the modern Min dialects.  The northern dialects of that time were then the origin of the modern Wu dialects.