fillergap

Fillergap refers to a closely examined phenomenon in linguistics known as a filler-gap dependency. In this pattern, a filler, typically a wh-form such as who, which, or what, appears in a fronted position, while a corresponding gap remains in the position where the filler originated. The two parts are linked across the sentence, signaling that the filler corresponds to the missing element at the gap.

An example is the English sentence: Which book did you say that Mary bought __? Here the filler is "which book" and there is a gap after "bought." The syntactic structure is analyzed as the filler moving to the front and leaving a trace or a null position (the gap) in the original location. The dependency between the filler and the gap must be established for the sentence to be considered well-formed.

In theoretical linguistics, filler-gap dependencies are central to discussions of movement and the structure of long-distance dependencies. The dominant approach in generative grammar posits that the filler moves to a higher position in the clause, creating a chain with a series of copies and a gap that serves as the trace of the moved element. This framework captures a wide range of phenomena, including subject and object extractions, as well as more complex extractions in embedded clauses.

Cross-linguistically, languages vary in how they realize filler-gap dependencies, including the permissible positions of gaps, the forms of fillers, and the strength of island constraints that limit extraction. In psycholinguistics, the filler-gap concept is also used to study processing, as readers and listeners hold the filler in working memory to connect it with the eventual gap, influencing reading times and parsing decisions. See also wh-movement and island constraints.