This study examined the effectiveness of Zipfian frequency at facilitating the acquisition of English prenominal past participles. Chinese middle school students (N = 103) were randomly assigned to a sequenced Zipfian frequency (SZF) group, a random Zipfian frequency (RZF) group, a balanced frequency (BF) group, and a control group. A mixed experimental design was used to detect the development of the learners' prenominal past participles. An untimed acceptability judgment task and a timed grammaticality judgment task were employed to assess the learning effect triggered by different types of frequency. Results of the timed grammaticality judgment task indicated that SZF was as effective as RZF and BF for learners to learn the grammatical prenominal past participles but more effective than RZF and BF for them to unlearn the ungrammatical ones in the midtest. Results of the untimed acceptability judgment showed that SZF was not superior to RZF and BF when learners learned the grammatical prenominal past participles, but more beneficial for them to unlearn the ungrammatical ones than RZF and BF in the post-and delayed posttests. Pedagogical implications for second language construction teaching are discussed.Keywords: Zipfian frequency; L2 acquisition; English prenominal past participles; Chinese speakers; untimed acceptability judgment task; timed grammaticality judgment task USAGE-BASED APPROACHES VIEW THE language learning process as statistically driven and experientially adaptive, starting with accumulating specific constructions to forming maximally abstract construction schemata in language users (Bybee, 2008;N. Ellis, 2012;N. Ellis & Ferreira-Junior, 2009; N. Ellis & LarsenFreeman, 2009;N. Ellis & O'Donnell, 2012;Eskildsen, 2009). In this process, the construction schema emerges from "the frequency-biased abstraction of regularities" within all instances of the target construction (N. 2009, p. 92). This view assumes that learners develop construction schemata statistically by analyzing concrete utterances when exposed to the target language (Kemmer & Barlow, 2000;Tomasello, 2003). Zipfian frequency distribution suggests that the frequency of words decreases as a power function of their rank in the frequency table. As one of the most important statistical properties of language and daily language use, it has been theorized to facilitate first language (L1) acquisition (Ambridge et al., 2006;Boyd & Goldberg, 2009;Childers & Tomasello, 2003;N. Ellis & Cadierno, 2009;Goldberg, 2006;Kidd, Lieven, & Tomasello, 2006), because some instances of a construction are used a geometrically greater number of times than others (N. Ellis, O'Donnell, & Römer, 2013; Larsen-Freeman, 2 The Modern Language Journal 100 (2016) 2011; Zipf, 1935), making the construction easier to anchor and therefore learnable. This account has been empirically substantiated by studies of L1 development (e.g., Goldberg, 2006;Goldberg, Casenhiser, & Sethuraman, 2004).EllisHowever, most experimental studies of second language (L2) learning u...