Inspired by the Sound-change Trajectory Method to identify the original written form of a word proposed by Mr. Pan Wuyun潘悟雲, it is proved that the lost iconographic symbols for the orphanized lexical item used as a verb which means crying (read as [da31]) in Wenling and Yuhuan dialects of Wu吳language is “Tuo (沱)”, which is Change-resistant form of the grade 1 of non-labial vowel in Guo Auslaut 果摄开口一等. “Tuo (沱)” is an adjective, which extends its meaning along the line of “abundant water” “rain drooping” and “tears drooping”. With the expansion of collocation range, it is extended to a verb which means flowing. The verb “Tuo (沱)” which means crying in Wenling and Yuhuan dialects is derived from the verb which means flowing, and is a feature word in Wenling and Yuhuan dialects.