This study explored learners' self-generated noticing of L2 input. It is motivated by previous research on input enhancement which suggested that learners are able to notice certain aspects of input on their own without any external means to direct their attention. Drawing on insights that learner-generated noticing is largely mediated by learnerinternal factors, this study specifically traced the effects of learners' first language (L1), and their current second language (L2) knowledge in generating noticing. Two L1 groups (Japanese and English) with no knowledge of the L2 (Korean) were exposed to written L2 input and probed for their noticing behavior under a "zero knowledge" condition, and a "some knowledge" condition (i.e., after they had been taught some L2 words). Results revealed that under the "zero knowledge" condition, both groups exhibited similar noticing patterns prompted by perceptual input properties. Under the "some knowledge" condition, however, the Japanese group seemed to have noticed more input items and processed them at a deeper level of understanding. Insights gleaned from the study are discussed with avenues for future research.A plethora of input enhancement research conducted thus far has focused on externally manipulating the presentation of input in order to increase the salience of certain target forms as a means to draw learners' attention to those forms. Accumulating results have shown that this type of externally generated enhancement does not necessarily facilitate learner noticing. Coincidentally, findings have revealed insights that learners are able to notice certain aspects of input on their own (i.e., learner-generated noticing), driven by their internal (as opposed to external) factors. Such insights suggestive of learnergenerated noticing, however, have mostly surfaced as an incidental byproduct, rather than a result of a direct inquiry (Gass et al., 2003) have since highlighted the need to focus on investigating learners' builtin, naturally driven preference for noticing and processing second language (L2) input.The present study attempts to directly explore learners' self-generated noticing of L2 input when left to their own devices by exposing learners to "unenhanced" input and examining what they noticed and what factors prompted their noticing. Based on previous insights that learner-internal factors such as their prior knowledge affect their noticing (e.g.study specifically traced the effects of two learner-internal factors-(a) their first language (L1) and (b) their current knowledge of L2-in generating learner noticing.