Building on Lardiere's (2009) Feature Reassembly Hypothesis and Ramchand & Svenonius's (2008) approach to language architecture, Slabakova (2009) proposed that features expressed covertly by context (e.g., tense in Chinese) are more difficult to acquire than features that have overt realizations (e.g., -ed in English) for the degree of difficulty in grammatical feature acquisition. The present study expands the testing ground of Slabakova's prediction by examining how L1-Chinese learners of English acquire progressive and perfective aspects that are encoded overtly and covertly, respectively.

In Chinese, zai and bare verb express progressive aspect; while perfective aspect is encoded in the suffix –le. English uses -ing to signal ongoing events, whereas bare verb expresses complete events. According to the cline of difficulty (Cho & Slabakova, 2014), covert to overt mapping is easier than overt to covert mapping. The mapping of progressive aspect from English to Chinese is overt to covert (-ing to bare), whereas the mapping of perfective aspect is covert to overt (bare to -le). Therefore, L1-Chinese L2-English learners are predicted to have more difficulties acquiring [perfect] than [progressive].

Fifty-three English native speakers and 17 L1-Chinese learners of English completed an Acceptability Judgment Test (AJT). Each item in the AJT contains a story and a target sentence. Participants were asked to judge given the story, whether the target sentence is acceptable or not based on a 4-point scale (1=unacceptable, 4=acceptable). Preliminary results show that both natives and learners (11 advanced and 6 intermediate, according to the proficiency test) differentiated –ing and bare form in progressive as well as perfective context. Intermediate learners were accurate in both progressive (expected) and perfective (unexpected) context, suggesting that overt/covertness is not a main factor in aspect acquisition, which disconfirms the cline of difficulty. Data from more intermediate and beginning learners will be presented and discussed.