Inflectional morphology has been considered as a particularly difficult area in second language (L2) acquisition (Lardiere 2008;Slabakova 2008). This paper reports on an empirical study investigating the L2 acquisition of English verbal morphology by Japanese young instructed learners. The aim of this study is to explore how the first language (L1) plays a role in the L2 acquisition of inflectional morphology, by applying the Feature Reassembly Hypothesis (FRH, Lardiere 2008) to a Japanese−English pairing. An elicited production task was administered to Japanese junior high school aged 12-15 (n = 102) and university students aged 19-20 (n = 30). The results show a difference with respect to accuracy rates and error types from previous L2 English studies, in terms of tense−aspect morphology. The findings provide evidence for the FRH's prediction that attributes morphological variability to L1−L2 contrasts in reassembly of feature matrices for morpholexical items. 1 Under the DM, it is assumed that lexical items are inserted into a syntactic node, where features on the lexical item have to form a subset of the features on the syntactic node. 2 The results of this study do not provide evidence for or against the IH, as the main goal of the study was to examine the predictive power of the FRH. However, further research aims to compare the two approaches.Languages 2019, 4, 1 2 of 24 transfer, while in others L2 processing was impeded. This is compatible with the FRH, which proposes that L2 processing depends on L1−L2 pairings, although any L1−L2 contrasts are ultimately acquirable. This study contributes to the current line of L2 generative research, by investigating the acquisition of different properties by beginner−intermediate young instructed learners in a different L1−L2 pairing.This study aims to address a question of how L1−L2 contrasts in feature assembly affect the L2 acquisition process of verbal morphology, by applying the FRH's key assumptions to a Japanese−English pairing. The FRH assumes two continuous learning processes (feature selection and feature assembly) and three determinants of learnability (the same feature, the different configurations, and morpholexical correspondence). For tense, Japanese has a verbal suffix −ta to encode [+past] (e.g., tazune−ta), which is morphosyntactically equivalent to English −ed (e.g., ask−ed). Japanese has a suffix −(r)u to denote [-past] (e.g., tazune−ru) with any person [1st/2nd/3rd person] and number [+/-singular] features which Chomsky refers to as phi−feature. 3 English, on the other hand, has the two forms: one is Ø (zero suffix) to denote [-past] with [1st/2nd person] and [+/-singular] (e.g., I/we ask, you/you ask); the other is −s to encode a specific bundle of three features [-past] with [3rd person] and [+singular] for subject−verb agreement (e.g., Jane/the girl/she ask−s). Turning to aspect, Japanese imperfective aspect form −tei−ru is associated with three aspectual features ([+progressive], [+habitual], and [+resultative]), while English be + −ing...