2024(In progress) Beyond the binary: Exploring native and non-native Korean perspectives on AI voice quality in language technology
2024(In progress) ChatGPT’s potential for foreign language learning: A student-centric evaluation of AI-assisted writing revision in advanced Korean classes
2024(In progress) Transcending educational boundaries: The impact of an online language and cultural exchange program among Generation Z learners of Korean
2024(Forthcoming) Yoonjung Kang, Jessamyn Schertz, Na-Young Ryu, Suyeon Yun & Sungwoo Han. Ch1. Vowels of heritage Korean in northern China. Studies on the Phonetics and Phonology of Heritage Languages, Cambridge: Cambridge University Press.
2023(Submitted) Na-Young Ryu. Students’ perceptions of utilizing AI chatbot as conversation partners for Korean speaking practice: Acceptance, benefits, and challenges. Innovative Methods in Korean Language Learning. 
2022Na-Young Ryu & Sunhee Kim.  인공지능 시대의 외국어 교육. 인공지능 시대 교사가 만드는 미래학교, 교육 과학사, 127-148. 
2022Na-Young Ryu. Investigating of the impacts of auditory-only and audiovisual perceptual training in the perception of Korean vowels [in Korean]. Journal of Korean Language Education. 33(2), 137-161.
This study examined the effects of online auditory-only (AO) and audiovisual (AV) training on the perception of Korean vowels. A total of 60 beginner learners of Korean participated in the Korean vowel identification as part of pre-test, AO or AV training, and post-test interventions, and they were assigned to an AO training group and an AV training group. The results showed that perceptual performance on Korean vowels in the AO- and AV- trained groups significantly increased after training, suggesting that perceptual learning of L2 speech can be enhanced by both methods of online perceptual training. In terms of the degree of perceptual improvement, there was no significant difference between the two groups at post-test, indicating that perceptual training with audiovisual tokens does not lead to a greater improvement in the perception of L2 vowels than training with only auditory tokens. 
2022Yujeong Choi & Na-Young Ryu. Digital storytelling using computer-based technology in second language learning. Edited by Fernanda Carra-Salsberg, Maria Figueredo, and Mihyon Jeon, Curriculum Design and Praxis in Language Teaching: A Globally Informed Approach, 123-133. 
This study presented a practical application of a language learning activity using digital storytelling. This project is meaningful in that it provided the learners with an opportunity to express in Korean their opinions or thoughts by enhancing their story through the use of voice, image, and sound, and then sharing it with other leaners. During the project the learners were able to practice certain grammar points that they had learned from the course, such as using Korean plain style speech and indirect quotations, as well as expanding their language skills with new vocabulary and sentence patterns not covered in class. The results of the student 
evaluation survey lead to the conclusion that writing scripts and producing videos for digital storytelling is helpful in learning Korean. 
2021SunHee Kim, Na-Young Ryu & Yongkook Won. Reliability of web-based French phoneme perception test, Journal of Digital Contents Society, 22(12),1-10.
This study introduces and assesses the reliability of a web-based phoneme perception training system created for Korean learners studying French. The suggested perception training test consisted of four subtests: consonant and vowel discrimination tests, and consonant and vowel identification tests. To assess the reliability of the perception training test, descriptive statistics of perception training results were reviewed first, followed by a criterion-referenced evaluation approach. The internal consistency and reliability of the perceptual training test were assessed using Cronbach’s alpha and dependability phi. The perception test had a Cronbach’s alpha of 0.71 to 0.97, which was generally high, and a dependability coefficient of 0.65 to 0.97. Low dependability ratings were found in a few subtests with a small number of items. It is suggested that these subtests be put together as one test to increase the test’s reliability. 
2021Na-Young Ryu. Assessing the effects of mobile assisted phonetic training on L2 sound perception. In E. Langran & L. Archambault (Eds.), Proceedings of Society for Information Technology & Teacher Education International Conference, 1091-1096.
This study evaluated the effectiveness of mobile-assisted phonetic training on the perception of the Korean three-way stop contrast by second language (L2) learners of Korean. It also assessed the relative influences of three types of corrective feedback provided during training on the perceptual learning of the contrast. The results showed that learners benefit from phonetic training using mobile phones to improve their perceptual knowledge of the L2 contrast. Moreover, while all types of feedback had a positive impact on L2 speech perception, correct/incorrect feedback alone led to greater enhancement than correct/incorrect feedback with additional audio-visual information. Taken together, these findings suggest that mobile-assisted phonetic training with simple feedback is most effective in developing learners’ perceptual accuracy of L2 contrasts and can result in facilitating L2 sound learning.
2020Na-Young Ryu, Yoonjung Kang & Sungwoo Han. The Effects of Phonetic Duration on Loanword Adaptation: Mandarin Falling Diphthong in Chinese Korean. Language Research 56(2), 225-261.
This study examines how Mandarin falling sonority diphthongs are adapted to a Chinese Korean dialect. It investigates how the subtle phonetic conditions of the source language affect adaptation, and if and how those phonetic effects differ in established loanwords compared to the on-line adaptation of novel loan forms. We found that in this bilingual population, while the Mandarin diphthongs are usually adapted as monophthongs, obeying the native phonological restriction against falling diphthongs, the retention of the input diphthongs in violation of the native constraint is also quite common. Additionally, we found that the choice of the monophthong vs. diphthong realization is strongly affected by the input phonetic duration and in particular, the durational difference among the different tones is robustly reflected in the adaptation patterns.

2019Na-Young Ryu & Yoonjung Kang. Web-based high variability phonetic training on L2 coda perception. Proceedings of the 19th International Congress of Phonetic Sciences, 482-486.
This study evaluates the effects of web-based high variability phonetic training (HVPT) on the development of L2 coda identification. 45 Mandarin learners of Korean were randomly assigned to receive coda-focused or vowel-focused training (both of which contained identical auditory input), or no training. Performance was assessed using an identification task before and after training, and a generalization test after training. The results demonstrate that the training groups overall improved their perception of Korean codas compared to the no-training group at post-test, suggesting that L2 learners benefit from online HVPT. Between the two training groups, the coda-focused group performed significantly better than the vowel focused group. This finding indicates that perception training for L2 sounds can lead to greater improvement when learners are consciously aware of their target sounds than by passive exposure to the target sounds. It was also found that learning effects gained from HVPT can be successfully transferred to new phonetic contexts.
2019Yoonjung Kang, Na-Young Ryu & Suyeon Yun. Contrastive hyperarticulation of vowels in two dialects of Korean. Proceedings of the 19th International Congress of Phonetic Sciences, 43-47.
Previous studies on vocalic hyperarticulation generally found that vowels become longer and more dispersed, i.e., more peripheral in vowel space, under hyperarticulation, rather than more spectrally distinct from contrasting vowels. This study examines contrastive hyperarticulation of vowels in the speech of 57 speakers of two dialects of Korean, Seoul Korean (South Korea) and Hamkyoung Korean (North Korea). Participants produced 24 sets of lexical minimal pairs three times, once in isolation (casual), once carefully as if speaking to a non-native speaker (careful), and once directly following the speaker’s production of the word’s lexical minimal pair (contrastive). In both dialects, we found a statistically significant effect of speech condition (contrastive > careful > casual) on vowel duration, degree of dispersion, and spectral distance between contrasting vowel pairs. A closer inspection of the data shows, however, that the evidence for spectral contrast enhancement independent of dispersion is inconclusive.
2018Na-Young Ryu. Perception of Korean vowels by English and Mandarin learners of Korean: Effects of acoustic similarity between L1 and L2 sounds and L2 experience [in Korean]. Journal of Korean Language Education 29(1), 1-23.
This paper investigates how adult Mandarin and English- speaking learners of Korean perceive Korean vowels, with focus on the effect of the first language (L1) and the second language (L2) acoustic relationship, as well as the influence of Korean language experience. For this study, native Mandarin and Canadian English speakers who have learned Korean as a foreign language, as well as a control group of native Korean speakers, participated in two experiments. Experiment 1 was designed to examine acoustic similarities between Korean and English vowels, as well as Korean and Mandarin vowels to predict which Korean vowels are relatively easy, or difficult for L2 learners to perceive. The linear discriminant analysis (Klecka, 1980) based on their L1 L2 acoustic similarity predicted that L2 Mandarin learners would have perceptual difficulty rankings for Korean vowels as follows: (the easiest) /i, a, e/ >> /i, Λ, o, u/ (most difficult), whereas L2 English learners would have perceptual difficulty rankings for Korean vowels as follows: (the easiest) /i, a, e, i, Λ/ >> /o, u/ (most difficult). The goal of Experiment 2 was to test how accurately L2 Mandarin and English learners perceive Korean vowels /i, Λ, o, u/ which are considered to be difficult for L2 learners. The results of a mixed-effects logistic model revealed that English listeners showed higher identification accuracy for Korean vowels than Mandarin listeners, indicating that having a larger L1 vowel inventory than the L2 facilitates L2 vowel perception. However, both groups have the same ranking of Korean vowel perceptual difficulty: i > Λ > u > o. This finding indicates that adult learners of Korean can perceive the new vowel /i/, which does not exist in their L1, more accurately than the vowel /o/, which is acoustically similar to vowels in their L1, suggesting that L2 learners are more likely to establish additional phonetic categories for new vowels. In terms of the influence of experience with L2, it was found that identification accuracy increases as Korean language experience rises. In other words, the more experienced English and Mandarin learners of Korean are, the more likely they are to have better identification accuracy in Korean vowels than less experienced learners of Korean. Moreover, there is no interaction between L1 background and L2 experience, showing that identification accuracy of Korean vowels is higher as Korean language experience increases regardless of their L1 background. Overall, these findings of the two experiments demonstrated that acoustic similarity between L1 and L2 sounds using the LDA model can partially predict perceptual difficulty in L2 acquisition, indicating that other factors such as perceptual similarity between L1 and L2, the merge of Korean /o/ and /u/ may also influence their Korean vowel perception.
2018Yujeong Choi & Na-Young Ryu. (2018). Project-based learning in Korean as a foreign language: A study on the production of book trailers and learners’ responses [in Korean]. Teaching Korean as a Foreign Language 49, 249-271.
The technological advances and ubiquitous use of Internet-access devices in recent years are changing the trajectory of language learning. Combining technology and project-based learning as a teaching method can help students gain knowledge and develop skills that help them solve problems and become responsible and autonomous in their learning. The development and sharing of project-based activities for classroom use is now becoming an important issue. In response to the need, this paper introduces the phases of planning and implementing a book trailer activity as an instruction model as part of the curriculum for use in an advanced Korean language class. A book trailer is a video that introduces a book and used in the classroom can help students exercise language, interaction, and complex thinking skills. Through the project learners highlight the story using their imaginations in a persuasive manner. The paper also discusses the results of implementation of the activity with learner responses on the benefits of the project. The results of the learners’ responses suggest that after this activity they better understood the content of the books, felt more confident in reading Korean literature, and were able to understand new vocabulary and grammar in the context.
2018Na-Young Ryu. Korean vowel identification by English and Mandarin listeners. Effects of L1 vowel inventory size and L1-L2 acoustic similarity. Toronto Working Papers in Linguistics 40, 1-13.
This paper examined how English and Mandarin listeners identify Korean vowels, focusing on native (L1) vowel inventory size and acoustic similarity between native and second language (L2) vowels. It was found that English listeners (with a larger vowel inventory) have higher identification accuracy scores for Korean vowels than Mandarin listeners (with a small vowel inventory), supporting the predictive role of vowel inventory size in non-native perception. To predict perceptual difficulties for L2 listeners, linear discriminant analysis (LDA) was undertaken. The LDA model predicted that English listeners will have the most perceptual difficulties with Korean vowels [o, u], while Mandarin listeners will have the most perceptual difficulties with [ɨ, ʌ, o, u]. The results of a Korean vowel identification task revealed that both groups showed the same perceptual difficulty order: ɨ>ʌ> o > u, indicating that acoustic similarity between L1 and L2 vowels partially predictsvowel perceptual difficulty for L2 listeners.
2017Na-Young Ryu. A comparative acoustic analysis of Korean vowels by native and non-native speakers. The Journal of the Acoustical Society of America 142, 2726.
The primary purpose of this study is to examine L1 transfer in L2 vowel acquisition (Flege 1995,1996) by comparing L1 vowels with L2 Korean vowels produced by Korean native speakers and both Mandarin and English learners of Korean. It would predict which L2 Korean vowels are relatively difficulty or easy to produce for the non-native speakers based on acoustic similarities and dissimilarities between their L1 vowels and L2 Korean vowels. A total of 68 female speakers participated in a word-list reading task. For acoustic analysis, the formant frequencies (F1 and F2) and vowel duration were measured. Results demonstrated that there were cross-language differences in both vowel quality and duration. Both Mandarin and English learners of Korean perform well when producing Korean [a, i] vowels, but have difficulty producing Korean vowel contrasts [ʌ]-[o], [o]-[u], [ɨ]-[u]. In terms of vowel duration, Korean vowels were the shortest, English vowels were the longest, and Mandarin vowels were intermediate between the two. Overall, the L2 Korean vowel duration of both Mandarin and English speakers was too short, compared to their L1 vowel productions, to have a Korean native-like performance of vowels.
2017Na-Young Ryu. Perception of Korean contrasts by Mandarin learners: The role of L2 proficiency. Toronto Working Papers in Linguistics 38, 1-20.
This paper examines how Mandarin learners, whose native language has only a binary laryngeal contrast, acquire the Korean three-way laryngeal contrast in stops and affricates. Two perception experiments are reported with a focus on L2 language proficiency. The results reveal that most Mandarin learners do not reach the same level of perceptual discrimination accuracy as native speakers; however, advanced learners perceive contrasts more accurately than beginner and intermediate learners. In addition, Mandarin listeners are more successful at perceiving Korean aspirated stop and affricate contrasts compared to fortis and lenis regardless of L2 proficiency. Also, lenis is least likely to be differentiated perceptually by Mandarin listeners across all proficiency groups. This suggests that they lack attention to f0, which is the most relevant dimension for native Korean listeners to discriminate lenis from fortis and aspirated consonants.
2016Na-Young Ryu. Effects of L2 proficiency on Mandarin speakers’ perception of Korean stops and affricates [in Korean]. Journal of Korean Language Education 27(4), 25-56.
This study investigates the degree of categoriality and discrimination accuracy in the perception of the three-way contrast in Korean stops and affricates by Mandarin speakers. The participants for this study include 44 Mandarin speakers who differ in Korean proficiency level and a control group of 13 native Korean speakers. Perceptual accuracy is assessed through an AX discrimination and an identification task. The result indicates that L2 proficiency plays a significant role in non-native speech perception. Overall, Mandarin listeners with more Korean language proficiency respond to the contrasts more like native Korean speakers than those with less proficiency. However, Mandarin learners of Korean have more difficulty perceiving lenis than aspirated and fortis, while they have less difficulty distinguishing aspirated from lenis and fortis regardless of their proficiency level in Korean. This finding suggests that Mandarin learners rely solely on VOT, which is a primary cue in their native language, when differentiating the Korean contrast, whereas native speakers of Korean use both VOT and F0 to distinguish the contrast. In light of this observation, Mandarin speakers who learn Korean as a foreign language need to focus on both VOT and F0 in order to increase their accuracy in the perception of the Korean contrasts.
2013Na-Young Ryu & Sung-Hoon Hong. Schwa deletion in the conversational speech of English: the role of linguistic factors. Linguistic Research 30(2), 313-334.
In this study we investigate schwa deletion and the role of three linguistic factors based on the Buckeye Speech Corpus (Pitt et al. 2007). This study provides evidence that schwa deletion is strongly influenced by stress environment (pre-stress position vs. post-stress position), sonority distance between two consonants surrounding an unstressed vowel [ə], and lexical frequency of the word containing the schwa. Stress environment affects schwa deletion in such a way that schwa is more likely to delete in post-stress position than in pre-stress position. As for the effect of sonority, schwa deletion is more likely to occur when there is a greater difference in sonority between the two consonants that appear before and after the schwa. With respect to word frequency, schwa deletion is less frequent in low frequency words than in high frequency words. We conduct a logistic regression analysis to find out how influential these factors are. The results of the regression analysis show that stress environment is the most pervasive, sonority the next, and lexical frequency the least influential factor that affects schwa deletion.
2010Na-Young Ryu & Sung-Hoon Hong. Variable vowel adaptations of English word-final stops in Korean loanword phonology. Studies in Linguistics 17, 143-160.
This paper examines the patterns of vowel epenthesis in English loanword adaptation that occur when English loanwords that end in postvocalic word-final stops are borrowed into Korean. We then provide a variable rule analysis of the three vowel epenthesis patterns: vowel epenthesis, no vowel epenthesis and variable vowel epenthesis, according to four linguistic factor groups, the tenseness of pre-final vowel (tense vs. lax), the voicing of the final stop (voiced vs. voiceless), the place of articulation of the final stop (coronal vs. labial vs. dorsal), and the number of syllables (monosyllabic vs. polysyllabic). Our analysis reveals that ‘tense’, ‘voiced’, ‘coronal’, and ‘monosyllabic’ are, in this order, the most significant factors for vowel epenthesis, whereas ‘labial’, ‘lax’, ‘polysyllabic’, ‘dorsal’, and ‘voiceless’ are the most crucial factors for no vowel epenthesis. It is also found that variable vowel epenthesis is most likely to occur when the factors are set as ‘lax’, ‘coronal’ and ‘voiceless’.