Null Arguments and Wh-in-situ

In this article I explore a variety of languages to show that there is a correlation between two different linguistic phenomena, wh-in-situ and the occurrence of null arguments, and derive a conclusive prediction that languages with D(iscourse)- based null arguments do not move wh- words to form a wh-interrogative sentence. To account for this correlation it is assumed that there exists an invisible D-linker connecting between a preceding utterance and a current uttering sentence containing null arguments. I argue that the existence of D-linker is conceptually necessary and valid in terms of the discourse structure provided by the centering theory, and can be proved to be real on the basis of empirical data. Finally I suggest a formulated schema as a general proposal to answer the question of why D-based null arguments block wh- movement and claim based on the empirical evidence that the general proposal can make a correct prediction that wh-movement cannot take place in languages with D-based null arguments since it results in intervening the association of a D-linker with the following null argument.