Cross-linguistic relations between quantifiers and numerals in language acquisition: Evidence from Japanese David Barner a, * , Amanda Libenson b , Pierina Cheung c , Mayu Takasaki c,d a Department of Psychology, University of California, San Diego, La Jolla, CA 92093, USA b Department of Communication Sciences and Disorders, MGH Institute of Health Professions, Boston, MA 02114, USA c Department of Psychology, University of Toronto, Toronto, Ont., Canada M5S 3G3 d Japanese Program, Department of German Language and Literature, Queen’s University, Kingston, Ont., Canada K7L 3N6 article info Article history: Received 30 July 2008 Revised 27 November 2008 Available online 21 January 2009 Keywords: Counting Quantifiers Bootstrapping Language acquisition Semantic development Number Japanese abstract A study of 104 Japanese-speaking 2- to 5-year-olds tested the rela- tion between numeral and quantifier acquisition. A first study assessed Japanese children’s comprehension of quantifiers, numer- als, and classifiers. Relative to English-speaking counterparts, Japa- nese children were delayed in numeral comprehension at 2 years of age but showed no difference at 3 and 4 years of age. Also, Japanese 2-year-olds had better comprehension of quantifiers, indicating that their delay was specific to numerals. A second study examined the speech of Japanese and English caregivers to explore the syntactic cues that might affect integer acquisition. Quantifiers and numerals occurred in similar syntactic positions and overlapped to a greater degree in English than in Japanese. Also, Japanese nouns were often dropped, and both quantifiers and numerals exhibited variable positions relative to the nouns they modified. We conclude that syntactic cues in English facilitate bootstrapping numeral meanings from quantifier meanings and that such cues are weaker in classifier languages such as Japanese. Ó 2008 Elsevier Inc. All rights reserved. Introduction Early in language development, children acquire words rapidly, learning up to 10 words a day from 18 months of age (Bates & Goodman, 1997; Caselli, Casadio, & Bates, 1999; Fenson et al., 1994; Gold- field & Reznick, 1990). Children’s early vocabularies are filled with names for things and even include a sprinkling of words that denote actions and events (Nelson, Hampson, & Shaw, 1993). However, before 2 years of age, most children lack words that denote the properties of sets. For example, quantifiers 0022-0965/$ - see front matter Ó 2008 Elsevier Inc. All rights reserved. doi:10.1016/j.jecp.2008.12.001 * Corresponding author. Fax: +1 858 534 7190. E-mail address: barner@ucsd.edu (D. Barner). Journal of Experimental Child Psychology 103 (2009) 421–440 Contents lists available at ScienceDirect Journal of Experimental Child Psychology journal homepage: www.elsevier.com/locate/jecp