The L2 acquisition of English articles and noun Phrases by Thai learners

English is widely considered as one of the most significant languages which plays a vital role in a wide range of domains, including in and outside educational settings. In second language (L2) acquisition of English, however, many L2 learners encounter difficulties with certain aspects, including English noun phrases (NPs) and the English article system. In the Thai context, many Thai learners of L2 English have the persistent problems with those linguistic aspects in their English acquisition.This research explores the acquisition of the English article system and NPs by Thai L2 learners of English who reside in Thailand and have limited L2 input exposure. 118 Thai participants, divided into three different English proficiency level groups (42 intermediate, 43 upper-intermediate and 33 advanced groups), were recruited into this study and asked to complete three tasks: the count-mass grammaticality judgment (GJ) task, the forced choice elicitation (FCE) task, and the production task (PT). The study aims at examining the Thai learners’ (re)setting of parameters (i.e., the Nominal Mapping Parameter (NMP), proposed by Chierchia (1998) and the Article Choice Parameter (ACP), proposed by Ionin (2003) and Ionin et al. (2004)) to the appropriate settings for English and investigating the role of semantic universals (definiteness and specificity) and an article preference in their English article choice.The results from the FCE and PT data show that most of the Thai participants made use of English articles more than they omitted them. It is argued that these results can reflect the learners being in the process of resetting of the NMP from the NMP setting of Thai, whose NPs have no articles, to the NMP setting of English, whose NPs have the article system. However, the statistical analysis from the GJ data reveal that only the advanced group had high ability in differentiating between English count and mass nouns at the level consistent with the control group (native English speakers). The results are interpreted that most of the Thai learners were being in the process ofresetting to the NMP setting of English, but only the advanced learners, indicating native-like ability in making a distinction between the two English noun types, could succeed in resetting their NMP to the target setting of the NMP.In relation to the Thai learners’ English article choice, the results from the FCE and PT data suggest that their L2 English article choice was affected by the semantic universal features: definiteness and specificity, indicating UG access, mainly in that fluctuation between the definiteness setting and the specificity setting of the ACP as well as the specificity article use patterns were demonstrated in their English article choice with the conflicting semantic contexts, especially [-definite, +specific] contexts. The results are interpreted that the Thai learners showed article difficulty with the specificity effects and thus that their article errors did not seem to be random. However, it was also found in the study that the Thai learners had an article preference in their choice of English articles. They indicated a preference for the in their English article choice. It is, thus, argued that apart from the semantic universals, an article preference which the learners had was likely to be a key factor, with which they had a tendency to connect English article choice