In the second language (L2) acquisition context, poverty of the stimulus is defined as a situation where neither incidental input nor instruction provide direct evidence for a particular property in the L2. Research has shown that L2 acquisition is nonetheless possible in such conditions, even when the L2 speakers' first language differs from the L2 in the relevant respect. In other words, L2 properties can (in some cases) be acquired despite the absence of direct evidence in the input for the given property. However, even when direct evidence of an L2 property is available through ambient input or instruction, research findings—along with the personal experiences of many L2 learners—show that acquisition of that property does not always proceed as might be anticipated. This paper reflects on how acquisition proceeds in light of ambient input, instructed input, and absent input, and identifies a key commonality in the role of input, regardless of the input context. The paper draws on data from a range of studies, with a focus on work by the present author on L2 acquisition in Japanese, Korean, and German.

This keynote article discusses the issue of crosslinguistic influence (CLI) in third language acquisition. I argue that CLI should be seen as co-activation of structures in previously acquired languages; it happens property by property, and its source can be either or both previously acquired languages. The subtractive language groups design, a relatively new methodological choice for experimental design and its advantages are presented. An extended example of how feature bundles become adjusted in the third language is explored, and new syntactic ideas (e.g., parametric hierarchies) are examined with a view to establishing whether they are supported by experimental findings thus far available. Some experimental evidence is reviewed with an emphasis of studies that examine Japanese. Other factors that can affect CLI, as predicted by the Scalpel Model, are also discussed. The overall message is that L3/Ln acquisition affords valuable insights to investigating language from a formal perspective.

This study examined the effects of meaning and form processing of unknown words on incidental vocabulary learning in Japanese reading. 78 Chinese college students majoring in Japanese were divided into three task groups: “First language (L1) meaning writing,”“Hiragana form writing” and “read-only (control).” All participants were asked to answer some comprehension questions and those involved in the meaning and form processing task were required to complete the tasks they were assigned to. After the reading activity, two unexpected immediate vocabulary posttests (the L1 to second language (L2) translation test and the word-form recognition test) were carried out to test the effect of 8 target words. The results show that in the L1 to L2 translation test, the “L1 meaning writing” and the “Hiragana form writing” can promote learning, and both have the same effect. Additionally, it is confirmed that compared with the “L1 meaning writing,” the “Hiragana form writing” is more effective in the word-form recognition test.