The Formation of "难道" and Its Grammaticalization

The adverb 难道 was originally two independent language units 难 and 道.Because of their neighboring syntactical positions,they were linearly combined to form a fixed disyllabic compound.As its meaning underwent an evolutionary process from a notional word to a functional word,from the original meaning difficult to saytonot sure,the word 难道 began to take on a specific and interrogative proposition to express the speaker's certain subjective judgment or supposition,on the basis of which the word further became a functional word.When the word is used to express the speaker's real value judgment of a doubtless question,it began to lose its concrete lexical meaning and evolved into a grammatical marker indicating rhetorical question.