The aspect hypothesis (Andersen & Shirai, 1994) proposes that language learners are initially influenced by the inherent semantic aspect in the acquisition of tense and aspect (TA) morphology. Perfective past emerges earlier with accomplishments and achievements and progressive with activities. Although this hypothesis has been extensively…

If first language is rational in the sense that acquisition produces an end-state model of language that is a proper reflection of input and that optimally prepares speakers for comprehension and production, second language is usually not. This paper considers the apparent irrationalities of L2 acquisition, that is the shortcomings where input…