Floating Numeral Quantifiers as an Unaccusative Diagnostic in Native, Heritage and L2 Japanese Speakers Running head: Unaccusativity in three Japanese grammars

This study investigates the knowledge of unaccusativity in Japanese native, heritage, and second/foreign language speakers with respect to licensing of floating numeral quantifiers (FNQs) by unaccusative and unergative subjects (the FNQ diagnostic). Two acceptability judgment experiments were conducted to examine (i) whether and how judgments of the three populations differ with respect to the FNQ paradigm and (ii) whether and how manipulations of agentivity of subjects and telicity of events affect their judgments of the FNQ diagnostic. Our findings show that (i) the native and heritage speakers’ knowledge about the FNQ diagnostic are largely indistinguishable from each other, (ii) some L2 speakers’ judgments show signs of initial development of the knowledge of the FNQ diagnostic, and (iii) that telicity shows clear effects on the FNQ diagnostic with all three groups, while the effects of agentivity are subtle and detectible only with the native and heritage speakers.