Perspectives on a Critical Period for Language Acquisition: Implications for language research and practice

Jayeon Lim 국제언어인문학회 2005 인문언어 Vol.7 No.-

In recent years there has been much discussion about whether there is a critical, or sensitive period for language acquisition. Research on a critical period provides an excellent example around which we can organize a discussion of the behavioral and neural evidence. In this paper, the early history of critical periods and evidence for the existence of critical periods in various domains of human cognition and learning are reviewed. Followed by this overview, evidence for a critical period in both linguistic and nonlinguistic area are presented. The paper then provides some unresolved questions regarding a critical period in language acquisition and states what the outcome of this issues mean for an understanding of language acquisition. Finally the paper concludes with some educational implications of a critical period for practice.

Marking Temporal Expressions: Acquisition of the Lexical Aspect by Adult Korean Learners of English

Lim, Jayeon 한국영어교육학회 2004 ENGLISH TEACHING(영어교육) Vol.59 No.2

The present study provides the results of a cross-sectional study of 60 Korean learners of English. In particular, the study reports the acquisition process in order to provide the relative influence of lexical aspect on the second language (L2) acquisition of English simple past. The analysis examines the degree to which the learners’ appropriate and inappropriate use of verbal morphology in English simple past contexts. The findings showed that learners, except for the advanced, were significantly more successful in using English simple past morphology with telics (accomplishments and achievements) than with atelics (states and activities). These findings are consistent with the predictions of the Aspect Hypothesis, and partially consistent with previous research with L2 learners of English from other L1 backgrounds. Lexical aspect, however, does not always influence the forms that competed for simple past. The base categories were favored as alternative response categories for low and intermediate learners across all lexical aspectual categories. For high-intermediate learners, the base categories were favored as alternative response categories for both states and activities. The paper also includes some discussion of the future pedagogical implications in classroom settings.

Korean Learners’ Production of English Sound Contrast : Focusing on word-final // and /i/

Jayeon Lim,Misun Seo 아시아영어교육학회 2016 The Journal of Asia TEFL Vol.13 No.1

This study examines Korean L2 learners’ production of English sound contrast not attested in their L1, focusing on word-final // and /i/. L2 pronunciation error patterns such as vowel deletion and epenthesis were more frequently found in the low group than in the high group. Acoustic properties of lexical and epenthetic vowels were also different according to learners’ proficiency levels. The low group’s epenthetic and lexical vowels showed similar acoustic properties with respect to friction and vowel ratio and F1 and F2 midpoint values. On the other hand, the high group’s epenthetic vowels exhibited longer friction ratio, shorter vowel ratio, higher F1 and lower F2 than lexical vowels. While the low group did not distinguish epenthetic vowels from lexical vowels, the high group pronounced epenthetic vowels differently from lexical vowels, possibly as transitional vowels. As for word-final [] from // or /i/, both groups showed longer friction ratio for [] from /i/ than for [] from //. The findings suggest the use of production strategies by L2 learners is different from native speakers and is mediated by their proficiency levels.

Development of Production and Perception Abilities in Non-contrastive Fricatives by Korean EFL Learners

Jayeon Lim,Misun Seo 한국응용언어학회 2010 응용 언어학 Vol.26 No.3

This paper examines the production and perception of L2 sounds which are non-contrastive sounds in L1 by Korean L2 learners of English with different proficiency levels. Specifically, the study investigated the differences between two dissimilar types of L2 sounds: L2 sounds which are non-contrastive in L1 but occur as allophones of the same phoneme (i.e., [s]-[?]) and L2 sounds which do not occur at all in L1 (i.e., [z]-[?]). With regard to production, low and advanced levels showed different patterns according to pair types: better performance with [s]-[?] by low levels and with [z]-[?] by advanced levels. With regard to perception, no significant difference was observed between learners with different proficiency levels. Both levels exhibited higher performance with [s]-[?] than with [z]-[?]. The results suggest that perception and production are independently developed by L2 learners.

Effects of Minimal Pair Instruction in Perceptual Discrimination of Nonce Words by Korean Learners of English

Jayeon Lim 한국응용언어학회 2012 응용 언어학 Vol.28 No.2

This paper investigates perceptual discrimination of English sibilants by adult Korean learners of English. The experimental group of learners received instruction with a focus on minimal pairs of English sibilants embedded in their communicatively oriented English speaking class. The focus was put on providing input through minimal pairs followed by teacher feedback. The control group of learners were also placed in an English speaking class, but with no specific focus on English pronunciation. The pre- and posttests were measured using nonce words containing English sibilants in perceptual discrimination, in order to reduce any word familiarity effect. The results indicated a positive influence of the focused instruction on minimal pairs. Findings further indicated that other variables such as L1, position of target segment, and vowel context were at play along with instructional effects.

Input Enhancement in the EFL Learning of Present Perfect and the Lexical Aspect

( Jayeon Lim ) 현대영어교육학회 2007 현대영어교육 Vol.8 No.3

This paper investigates the classroom learning of English present perfect among 62 adult Korean learners. In particular, the study examined the effect of visual input enhancement and its relations to the lexical aspect of verbal predicates. The results showed that visual input enhancement had a positive role in that learners showed learning effect over the treatment period. In addition, learners' development of the target structure was dependent on the lexical aspect of verbs/verb predicates. Specifically, input enhancement effect was more prominently observed in telics than in activities and states. The findings are insightful in that not all structures are amenable to a similar amount of input enhancement and even those within a single grammatical category, effects of input enhancement may vary.

Covert Contrasts in Korean EFL Learners’ Interlanguage Phonology

( Jayeon Lim ),( Misun Seo ) 범태평양 응용언어학회 2023 Journal of Pan-Pacific Association of Applied Ling Vol.27 No.1

This study examined how Korean EFL learners in different proficiency levels attest contrasts of L2 phonology. To this end, twenty Korean EFL learners in high and low levels of English proficiency produced words with word-final contrasts of /∫/ vs. /∫i/, /t∫/ vs. /t∫i/, and /dʒ/ vs. /dʒi/. Acoustic analyses of lexical vs. epenthetic vowels and lexically vs. derivationally final sibilants were conducted. The results of the acoustic analyses revealed that Korean learners differentiated them at the acoustic level by employing different vowel ratios or F1 for the produced forms with a final lexical or epenthetic vowel which did not differ at the segmental level. On the other hand, the low group did not acoustically differentiate the two types of vowels after /dʒ/ at all. With the production of a final sibilant either lexical or derivational, Korean learners also made distinctions in terms of different frication ratios. The results of the study found L2 learners distinguish segmental contrasts acoustically, which is different from L1 speakers, and the proficiency level partially mediates this. The results implicate the existence of interlanguage phonology with its independent system.

Deeper Integrative Neural Network Analysis for Multi-level Omics Data

Jayeon Lim,Junsang Cho,JaeYoung Kim,Jiyeon Kim,SungHwan Kim 계명대학교 자연과학연구소 2019 Quantitative Bio-Science Vol.38 No.2

Recently, various machine learning methods have emerged for analyzing and interpreting the ever-expanding genetic data. In addition, new analytical tools for machine learning using statistical models, are being developed. Lim et al. [1] proposed the integrative deep learning to find the differentially expressed (DE) biomarkers using deep neural network with a single hidden layer. This method consists of the input layer, a hidden layer, the consolidation layer, and the output layer. They found that integrative deep learning method is stable and robust for analysis of the variation in the simulation datasets. In this study, we expanded the integrative deep learning method by including an additional hidden layer. The present expanded method consists of the input layer, two hidden layers, the consolidation layer and the output layer. The purpose of this study is to investigate the effect of the additional hidden layers on the performance of the previous method (integrative deep learning). We conducted a simulation study and compared the results with those from deep neural network with one hidden layer.

Intelligibility and Comprehensibility in the Production of English Sibilants by Korean Learners

Jayeon Lim,Misun Seo 한국응용언어학회 2011 응용 언어학 Vol.27 No.3

This paper investigates intelligibility and comprehensibility in the production of English sibilants by Korean L2 learners of English. Identification and goodness of fit experiments were performed by native English speakers in order to measure intelligibility and comprehensibility. Various factors, such as position of English sibilants in words, frequency of words, types of English sibilants and proficiency of L2 learners were found to be influential on intelligibility and comprehensibility in a complex way. The effects of frequency and sibilant were inconsistent across positions, as measured by intelligibility and comprehensibility alike. The effect of frequency was inconsistent across sibilant pairs as measured by intelligibility, whereas the effect was consistent across sibilants according to comprehensibility. In addition, the effect of position was inconsistent across proficiency levels measured by comprehensibility, but not by intelligibility. The results of the study indicate that intelligibility and comprehensibility of L2 speech may be partially independent.

Phonological Memory and L2 Production/Perception Accuracy

( Jayeon Lim ),( Misun Seo ) 글로벌영어교육학회(구 호남영어교육학회) 2016 Studies in English education Vol.21 No.3

This study examined the relationship between Korean learners`` phonological memory (PM) and production/perception accuracy of the word-final sound contrasts not observed in their L1. Korean learners`` production/perception accuracy of /∫/ vs. /∫i/, /t∫/ vs. /t∫i/, and /d□/ vs. /d□i/ was found to be significantly related to PM measured by an English-based nonword serial order recognition test. In particular, PM nonwords with shorter list lengths of 4 and 5 items illustrated a significant correlation with L2 production/perception accuracy. On the other hand, PM measured by an English word serial order recognition test did not show any significant correlation with L2 production/perception accuracy. These results manifest that PM measured by nonwords, free from the interference of familiarity or long-term memory, is a more reliable predictor of language learning. The effect of list length was found in PM. Thus, higher accuracy was attested with shorter list length. In addition, the effects of list length and L2 proficiency level were different in the word/nonword PM tests. With PM words, the high level learners exhibited higher PM capacities than the low level learners across all list lengths. However, with PM nonwords, there was a positive relationship only between the L2 proficiency level and shorter list lengths. High level learners showed better PM than low level learners when the cognitive demand is relatively lower.