In daily communication, we learn, remember, and adjust the way we understand and use language in response to the ever-changing environment around us. This chapter provides an up-to-date review of the psycholinguistic studies that investigated syntactic persistence in both first language (L1) and second language (L2) processing, with a focus on the change of syntactic representation and the learning of grammatical rules. We focus on the grammatical knowledge conceptualized in structural priming (short-term syntactic persistence) and syntactic adaptations (cumulative and long-term persistence) studies. On the one hand, language users adjust the weighting of relevant syntactic structures, leading to reusing syntactic structures that are recently encountered. On the other hand, through active prediction of upcoming words by making parsing decisions, the parser develops the ability to draw on multiple information for parsing in sentence comprehension. Topics such as L1/L2 differences, language proficiency, and cross-language priming are reviewed for a better understanding of the development of abstract syntactic representations in L2 learning as a result of the increased experience with target structures in the target language. We also discuss the nature of structural persistence effects in online processing and their implications for language learning and teaching.