Studies focusing on the type of language knowledge attained

A number of studies that investigated adult morphosyntactic learning using a miniature language paradigm also tried to elucidate the nature of the language

knowledge gained by the learners as a result of exposure (among others, Francis et al., 2009; Grey, Williams, & Rebuschat, 2015; Rebuschat & Williams, 2012; Robinson, 2002; 2005; Rogers, Révész, & Rebuschat, 2015). For example Rebuschat and Williams (2012) report on two experiments that used a modified natural language with English lexis and German word order (V2 word order in main clauses and OV order in main and subordinate clauses). In experiment 1, 20 L1 English speakers were exposed to 128 aural sentence stimuli under incidental learning conditions and simultaneously asked to judge their semantic plausibility. The stimuli included four word order patterns: V2 in main clauses, with the first element being a phrase or a sentence, V-final in main clauses, and V-final in subordinate clauses. In the testing phase both the experimental and the control

group (15 participants) were administered an aural GJT consisting of 64 sentences (half of which ungrammatical).

The test revealed no significant learning effect, nor a significant difference between the experimental group and control. However, the development of conscious knowledge in the learning process, assessed through an analysis of confidence ratings and knowledge source attribution, emerged as a critical modulating factor. In particular, the group who had developed awareness of the language rules showed significant learning effects and there was a significant advantage compared to both the unaware group and the control group, specifically in the case of accuracy in the identification of ungrammatical sentences.

In experiment 2, 30 L1 English speakers were trained in the same modified natural language (15 controls) and a similar design was adopted although fewer syntactic patterns were presented in the exposure. In this second study the experimental group performed significantly above chance and outperformed the control group in the GJT. However, contrary to what was found in experiment 1, this time the advantage emerged in the accurate judgment of grammatical sentences. Again, the analysis of the confidence ratings and the source attribution revealed that although participants could not verbalize the rules of the language, partial awareness of its syntax was related to a positive

performance in the experimental group.

Building on the methodology developed in Williams and Kuribara (2008), Grey, Williams and Rebuschat (2015) deployed Japlish to investigate morphosyntax

acquisition in a third language under incidental learning conditions. The study tested 36 L1 English low and high proficient learners of Spanish (15 and 21 respectively),

immediately after aural exposure to the language (128 aural sentence stimuli) and after a two-week lag. An aural AJT (acceptability judgment test) was deployed as a measure of

receptive word order learning. Unlike previous studies with Japlish, the acquisition of the relationship between thematic structure and case marking was investigated using a picture matching task (PMT). The results of this study at immediate posttest revealed that learners performed significantly above chance on word order but not on case marking. However the results of the delayed posttest showed that gains on word order were maintained and accuracy on case marking had improved. A comparison between the scores of low and high proficiency Spanish speakers also revealed that for the advanced group there was a significant correlation between the total number of

semesters of Spanish study attended by the students and the AJT performance at delayed posttest.

Unlike Williams and Kuribara (2008), this study included measures of awareness to investigate the extent to which the knowledge acquired during the instructional

process was implicit. Analysis of confidence ratings, source attribution and verbal reports showed that confidence in the response and reliance on intuition were the two factors that had a significant influence on accurate performance. Also, the verbal reports revealed that most learners were able to verbalize correct rules at least for noncomplex sentence patterns and some could provide correct exemplifications of how case marking worked, suggesting that incidental instruction had led to a grammatical knowledge representation that was largely explicit.

Finally, Rogers, Révész and Rebuschat (2015) used a modified natural language based on English and including 24 Czech nouns with nominative and accusative endings to test 42 English monolinguals (21 of which controls) on the acquisition of case

morphology under incidental learning conditions. The participants were exposed to auditory sentence stimuli (144 items including subject-object canonical and scrambled orders). In each trial they were also asked to perform a force-choice vocabulary task

whose purpose was to hinder sentence analysis. The result of a GJT administered immediately after exposure showed that there was a significant learning effect for the experimental group compared to controls, even if learning of the endings was only slightly above chance. The learning effect was driven mainly by the acquisition of one of the two forms (the accusative), a result reminiscent of what Robinson (2002, 2005) found for Samoan (in that case the locative marker was learnt better). There was evidence that participants acquired at least some implicit knowledge of the language morphosyntax during exposure as only GJT responses based on intuition were accurate significantly above chance and none of the participants could verbalize the

morphosyntactic rule.

Overall, the picture emerging from adult studies that looked at the nature of morphosyntax knowledge acquired by the participants as a result of exposure suggests that, at least for this age group, awareness of language regularities played a crucial role in supporting L2 attainment. However, in at least one study (Rogers et al., 2015) there was some evidence that above chance learning was associated to knowledge that was at least partially implicit.