This study reports on an empirical study, focusing on the declarative and procedural knowledge in English-speaking learners’ acquisition of the verbal identity condition in their second language Chinese grammars. While subjects and objects in English sentences are generally overt, both subjects and objects in Chinese can be ‘covert’. It is argued in this article that the absence of subjects and objects in affirmative answers to Chinese yes–no questions arises from TP ellipsis under a verbal identity condition (Simpson, 2014). A cross-modal self-paced reading task (SRT) and an acceptability judgment task (AJT) are involved in the study, and the results of the AJT show that all learner groups, like native Chinese speakers, judge answers with covert arguments under the verbal identity condition as more natural than those not under such a condition. In the SRT, however, beginner learners, but not intermediate and advanced learners, fail to show sensitivity to the verbal identity condition. These findings align with the Declarative/Procedural Model (Ullman, 2005, 2015), indicating that beginners rely on declarative, rule-based knowledge to evaluate grammaticality but lack proceduralized capacity to process covert arguments in real time. With increased exposure and proficiency, learners proceduralize grammatical computations, such as lexical identity checking, movement, and ellipsis, which enable them to acquire native-like sensitivity to the verbal identity condition in their procedural as well as declarative knowledge.
