Can adults learn L2 grammar after prolonged exposure under incidental conditions?

Abstract

While late second language (L2) learning is assumed to be largely explicit, there is evidence that adults are able to acquire grammar under incidental exposure conditions, and that the acquisition of this knowledge may be implicit in nature. Here, we revisit the question of whether adults can learn grammar incidentally and investigate whether word order and morphology are susceptible to incidental learning to the same degree. In experiment 1, adult English monolinguals were exposed to an artificial language (Kepidalo) that had case marking and variable word order: a canonical Subject-Object-Verb order and a non-canonical Object-Subject-Verb. In a five-session online study, participants received vocabulary training while being incidentally exposed to grammar, and completed a series of picture-selection and grammaticality judgment tasks assessing grammatical knowledge. Despite extensive exposure to input, and although performance on vocabulary increased significantly across sessions, learners’ grammatical comprehension showed little improvement over time, and this was limited to Subject-Object-Verb sentences only. Furthermore, participants were better at detecting word order than case marking violations in the grammaticality judgment tasks. Experiment 2 further increased the amount of incidental exposure whilst examining native speakers of German, which exhibits higher morphological richness. Testing was followed by a post-test metalinguistic awareness questionnaire. Although greater learning effects were observed, participants continued to have difficulties with case marking. The findings also demonstrated that language outcomes were modulated by learners’ level of metalinguistic awareness. Taken together, the results of the two experiments underscore adult learners’ difficulty with case marking and point towards the presence of a threshold in incidental L2 grammar learning, which appears to be tightly linked to prior first language experience. In addition, our findings continue to highlight the facilitative role of conscious awareness on L2 outcomes.

Redundancy can hinder adult L2 grammar learning: evidence from case markers of varying salience levels

“…In the case of learners who failed or struggled to develop at least a relatively basic knowledge of the novel lexicon, grammar learning outcomes were minimal, if not absent, as can be seen in Figures 3, 5. This strong link between participants' learning of the vocabulary items prior to the test and their development of knowledge about the grammatical regularities of the language appears to be a recurrent theme in artificial language studies (Martin and Ellis, 2012;Rebuschat et al, 2021;Kenanidis et al, 2023) and aligns well with previous findings from studies on L1 acquisition and ultimate attainment (Bates et al, 1988;Dąbrowska, 2018;Llompart and Dąbrowska, 2020). Irrespective of whether these two aspects of language are acquired simultaneously to the same extent or sequentially, efficient vocabulary learning appears to be necessary for getting the learning of basic syntactic information, such as how individual words can be combined to form sentences, off the ground, a claim that is at the core of usage-based accounts of language acquisition (e.g., Tomasello, 2003;Bybee, 2010).…”

“…Participants were auditorily exposed to Kesadalo, an artificial language that was modeled after Kepidalo ( Kenanidis et al, 2023 ). The artificial language consisted of ten nonce words, six nouns ( alg , velg , ird , prad , olb , flub ) that denoted aliens and four verbs ( mulek , dolek , var ek , birek ) which referred to four different transitive actions (catapult, chase, jump over, approach).…”

“…Earlier research suggests that, when first exposed to a novel language (or under incidental conditions), the cues that L2 learners are more likely to focus upon are largely determined by their prior L1 experiences ( McDonald, 1987 ; MacWhinney, 2001 ; Ellis, 2006 ). For example, studies examining thematic role assignment in transitive sentences have demonstrated that learners’ earlier experience with a morphologically impoverished L1 (e.g., English) leads them to over-rely on word order cues, hindering the processing and acquisition of morphosyntactic cues, such as case marking ( Grey et al, 2014 ; Rogers et al, 2016 ; Kenanidis et al, 2023 ). Such processing strategies can have an even more detrimental effect on grammatical morphemes that are largely redundant given that such cues are generally not essential for the correct interpretation of sentences and, consequently, are often overlooked ( VanPatten, 2006 ) or blocked by learners’ attention to cues that are more familiar to them ( Wulff and Ellis, 2018 ).…”

“…On the one hand, if redundant cues do indeed increase learnability, this should be reflected in superior performance in the redundant case marking groups in both experiments relative to the no case marking group. On the other hand, if redundant grammatical cues are processed only after the nonredundant ones have been processed ( VanPatten, 2006 ), and given L2 learners’ difficulty with processing and learning novel case markers ( Rogers et al, 2016 ; Kenanidis et al, 2023 ), then we would expect no differences between groups. Finally, if the salience of the redundant case marking cues influences their detectability by learners, then we would expect to find stronger learning in the redundant case marking group of Experiment 2 compared to the low salience redundant group of Experiment 1.…”