Deciding the Referent of a New Word: The Acquisition of Classifier Weiyi Ma and Peng Zhou 1. Introduction Upon hearing a new word, listeners are faced with an inherently complex task of deciding the referent of the word. One useful cue to the meaning of a new noun is the classifier preceding the noun. Although classifiers are not generally a feature of English or other European languages, classifier-like constructions are used with certain nouns in English. Thus, X in “a sheet of X” should refer to a broad, flat piece of object, while Y in “a chunk of Y” most probably refers to a thick, solid object. Classifiers can be exceptionally important for word learning in languages like Chinese where classifiers are obligatory when the number of entities needs to be specified. For example, the phrase “three people” should be expressed as “three classifier people” in Chinese. Mandarin has a generic classifier (ge), which is the most common classifier, and multiple specific classifiers indicating the shape (tiao2: long and slender objects; zhang1: flat objects), function (liang4: ground vehicle; sou1: water vehicle), or other physical properties of the object. The acquisition of Mandarin classifiers is a protracted process. Research has shown that 2-year-old Mandarin learners did not have a reliable understanding of classifiers, while the comprehension of classifiers developed rapidly between 3 and 5 years of age (Chien, Lust, & Chiang 2003; Li, Huang, & Hsiao 2010). In addition, children were able to demonstrate adult-like knowledge of classifiers around 6 years of age. However, their ability to appropriately produce classifier still continues developing well beyond 6 years of age (Chien et al., 2003; Li et al., 2010). 2. Present study This study aims to 1) determine if 3- to 5-year-old Chinese learners can use classifiers to determine the referents of new words, and to 2) document the development of classifiers. * Weiyi Ma, School of Human Environmental Sciences, University of Arkansas, Fayetteville, AR, 72701, weiyima@uark.edu. Peng Zhou, Department of Foreign Languages and Literatures, Tsinghua University, Beijing 100084, China. W.M. is supported by The University of Arkansas Startup Fund and the Provost's Collaborative Research Grant. P.Z is supported by Tsinghua University Initiative Scientific Research Program [2016THZWLJ14]. © 2019 Weiyi Ma and Peng Zhou. Proceedings of the 43rd Boston University Conference on Language Development, ed. Megan M. Brown and Brady Dailey, 387-390. Somerville, MA: Cascadilla Press.