Producing filler-gap dependencies: Structural priming evidence for two distinct combinatorial processes in production

•A model of structural priming based on Tree-Adjoining Grammar is developed.•The lexical boost effect for that-priming occurred.•But only when prime and target both contained filler-gap dependencies.•Or when neither did, confirming the prediction of the model.•Speakers use distinct prcesses for cross-clausal filler-gap dependencies.