This is an exploratory study of how both native English speakers and L1-Mandarin L2-English learners judge different types of indefinites in both existential there-constructions and copular constructions with an indefinite subject. Unlike English, Mandarin lacks an a/one distinction, has two different types of existential constructions, and lacks numeral partitives. It is argued that target differentiation among indefinite types and syntactic constructions presents a Poverty of the Stimulus problem. Learners are found to overcome this problem: while there is limited evidence of L1-transfer from Mandarin to English, the learners largely exhibit the same patterns as native speakers in an acceptability judgment task. It is argued that a universal Gricean principle helps learners acquire the a/one distinction.
