About

Dr. ZhaoHong Han is a Professor of Applied Linguistics and the Director of the Center for International Foreign Language Teacher Education (CIFLTE) at Teachers College, Columbia University. She has served as Chair of the Department of Arts and Humanities from 2018 to 2020, leading the department with a focus on innovative, transparent, and equitable practices while promoting academic excellence. Her scholarly interests broadly encompass second language learnability and teachability, and their interface, with particular emphasis on topics such as fossilization, crosslinguistic influence, corrective feedback, second language thinking for speaking, reading and vocabulary development, input enhancement, second language input processing, task-based language learning, and foreign language teacher education. Dr. Han's work has been published extensively in journals and books, and she has been recognized with awards including the 2003 International TESOL Heinle and Heinle Distinguished Research Award and multiple Teachers College Outstanding Teacher Awards. She has served on editorial boards of prominent academic journals, including Applied Linguistics and Language Teaching, and has been a keynote speaker at numerous international conferences on second language acquisition and teaching. Over the past twenty years, she has taught graduate courses, sponsored doctoral dissertations, and consulted for universities, contributing significantly to the field of second language acquisition and education.

Research topics

• Computer Science
• Psychology
• Artificial Intelligence
• Mathematics education
• Philosophy
• Cognitive psychology
• Cognitive science
• Linguistics
• Epistemology

Selected publications

• Modeling Ultimate Attainment in Foreign Language Learning in the Age of AI

  Preprints.org · 2025-04-21 · 1 citations

  preprintOpen access1st authorCorresponding

  Energy Conservation Theory for Second Language Acquisition (ECT-L2A) is an interdisciplinary model of human learning extended to the domain of foreign language acquisition (Han et al., 2017a, b; Han & Bao, 2023). Uniquely, it provides a unified mathematical account of two well-documented phenomena in foreign language learning: (a) differential ultimate attainment among older language learners, and (b) differential ultimate attainment between younger and older learners. In this article, we substantiate ECT-L2A by quantifying foreign language learning difficulty (D) as a function of the linguistic distance (n) between a learner’s first language (L1) and target language (TL). We mathematically confirm that D and the pair {n, ρ}- where ρ is the influence factor of the TL - have a quadratic and inverse relationship: D ~ n^2/ρ. By using AI-generated data, we enable quantitative mapping and crosslinguistic comparison of D for learners from different L1 backgrounds. These results are significant, both theoretically and practically.

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• On the nascency of ChatGPT in foreign language teaching and learning

  Annual Review of Applied Linguistics · 2025-03-01 · 2 citations

  articleOpen accessSenior authorCorresponding

  Abstract The emergence of ChatGPT as a leading artificial intelligence language model developed by OpenAI has sparked substantial interest in the field of applied linguistics, due to its extraordinary capabilities in natural language processing. Research on its use in service of language learning and teaching is on the horizon and is anticipated to grow rapidly. In this review article, we purport to capture its nascency, drawing on a literature corpus of 71 papers of a variety of genres – empirical studies, reviews, position papers, and commentaries. Our narrative review takes stock of current research on ChatGPT’s application in foreign language learning and teaching, uncovers both conceptual and methodological gaps, and identifies directions for future research.

  PublisherDOI

• Using game-mediated digital tasks to elicit data on incidental vocabulary learning

  2024-10-14

  book-chapterSenior author

  Over the last two decades, digital language learning has proliferated. However, our understanding of the scope and depth of such learning is still woefully inadequate. The need for empirical research that systematically tracks individual learners as they interact with digital learning platforms is immediate and urgent. This chapter reports on a study demonstrating how game-mediated digital tasks are used to elicit data on second language incidental vocabulary learning through a longitudinal, multiple-case design. The study followed three adult learners of English over a period of three months as they engaged in game-mediated tasks. Three types of data were collected: participants’ performance on tailor-made vocabulary tests, their learning logs, and their responses to process-oriented questionnaires and semi-structured interviews. Results indicated that game-mediated, digital tasks, coupled with digital measurement tasks and data on learner perceptions, can yield a credible picture of the dynamics of incidental learning in a game environment.

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• Editorial: Social physics and the dynamics of second language acquisition

  Frontiers in Physics · 2024-03-04

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  EDITORIAL article Front. Phys., 04 March 2024Sec. Social Physics Volume 12 - 2024 | https://doi.org/10.3389/fphy.2024.1392590

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• Chatgpt in and for second language acquisition: A call for systematic research

  Studies in Second Language Acquisition · 2024-03-13 · 42 citations

  articleOpen access1st authorCorresponding

  CA platforms are language models in that they simulate real-world language use, to a certain extent.A recent scoping review by Xiao et al. (2023) suggests that CA-aided interaction carries the flavor of authenticity, is motivating, enjoyable for language learners, and is used by teachers as a supplementary source of practice for language learners and a tool for formative assessment.This research, according to Xiao et al. (2023), has been dominated by an interest in users'-learners' more than teachers'-perceptions of their experiences, a sign likely of a commercially driven interest as well as an embryonic stage of academic research.A.I.-powered language models have evolved at a breathtaking pace.The recent release of ChatGPT (Generative Pre-trained Transformer) by OpenAI took the world by storm with its jaw-dropping capabilities, from natural language understanding to conversation generation, language translation, text summarization, grammar correction, paraphrasing, and more.Billed as a large language model, ChatGPT has been trained on an outsize (on the scale of hundreds of gigabytes) and diverse dataset of texts published on the internet on an array of topics, learning the statistical patterns and relationships between words and phrases in text.The end game is a mathematical architecture of hundreds of millions of parameters, resembling a neural network in the human brain capable of performing generative functionalities like the types aforementioned.It is anticipated that future iterations of ChatGPT will see an exponential growth of parameters and, hence, an ever more sophisticated algorithm, which, aided by Herculean computing power, will yield even greater human-like language capabilities (Metz, 2024;Rudolph et al., 2023).For such a gigantic, actual, and potential computer simulation of natural language usage, societal and academic reactions are mixed.Enthusiasts are exhilarated about ChatGPT's language modeling capabilities.Conversely, critics are gravely concerned that "the eerily humanlike chatbot" (Satariano & Kang, 2023) can do catastrophic harm to humanity.Other than its liability for spreading bias and controversial content, the fear of ChatGPT thwarting human learning potential and taking away human livelihoods looms large, so much so that governments are in disarray as to how to respond in terms

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• Age and attainment in foreign language learning: The critical period account stands

  Brain and Language · 2023-10-17 · 1 citations

  articleOpen access1st authorCorresponding
  PublisherDOI

• Exploring Co-adaptation in an Ecosystem of Dyadic Interaction

  Language Teaching Research Quarterly · 2023-12-01

  articleSenior author

  In the field of applied linguistics, Diane Larsen-Freeman is widely recognized, among her numerous contributions, as the originator of Complex Dynamic Systems Theory (CDST). Over the years since her seminal publication (Larsen-Freeman, 1997), CDST has evolved into a meta-theory that guides the field’s thinking on a variety of developmental phenomena, not least the study of second language acquisition. As its theoretical potency rises, so does the need to achieve a tangible understanding of CDST’s core constructs. In this paper, we empirically examine one such construct, co-adaptation, in the context of asynchronous dyadic interaction. A data corpus of 39 emails sent between two college students in China and the United States over the course of seven weeks is analyzed using NVivo 12. Co-adaptation is observed at the pragmatic, discourse, and linguistic levels. True to the spirit of CDST, we describe, and discuss the nuances of, our findings. Considering the novelty of our approach to data analysis, we end by reflecting on the limitations specific to our study, as well as worthwhile directions for future pursuits.

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• Teachers as Researchers: Exploratory Practice in Tunisian EFL Classrooms

  Studies in Applied Linguistics and TESOL · 2023-12-11

  articleOpen access1st authorCorresponding

  This Special Issue is dedicated to teachers’ exploratory practice research (Allwright, 2005; Allwright & Hanks, 2009). It showcases nine studies conducted by Tunisian EFL teachers in their own classrooms.
 In the publishing world of TESOL and applied linguistics, despite a proliferation of journals and edited volumes in recent decades, there remains hardly any space for practitioner research. Book publishers and journal editors, driven in part by concerns about profit margins, tend to reject this type of research (unabashedly) citing, as pretexts, the lack of geographical reach or lack of name recognition among contributors. Against this backdrop, this Special Issue counters the commercial mindset and helps fill a longstanding void in TESOL and applied linguistics literature. It illustrates how exploratory practice research can be done and illuminates the potential of practitioner research and the largely untapped ingenuity of practitioners.
 As an introduction to this Special Issue, we will, briefly, discuss the research-practice divide phenomenon and describe the genre of exploratory practice (EP). After, we present a synopsis of nine EP studies. We conclude by emphasizing the unique role of EP in advancing foreign language instruction and suggesting ways to substantiate it.

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• In English Medium Instruction you can walk and chew gum

  Frontiers in Psychology · 2023-03-22 · 10 citations

  articleOpen access1st authorCorresponding

  In English Medium Instruction (EMI), one of the biggest challenges is reportedly the teachers' own lack of English language proficiency. Helping teachers to improve their proficiency while learning about pedagogy is critical to achieving reasonable success in EMI. This article is contextualized in an English language teacher education program conducted in Tunisia. Specifically, I zoom in on a training task that had trainees reading an academic textbook and posting takeaways on an asynchronous platform over a four-week period. The corpus, comprising 50 journal entries produced by five teacher trainees, was analyzed, first using automated tools for natural language processing and then through human coding, for a combination of quantitative and qualitative perspectives, and with a view to deriving a comprehensive understanding of learning as manifested on multiple levels - psychological, cognitive, and linguistic. Results show impressive learning gains both in content and language. I conclude by discussing the findings and implications for EMI.

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• Critical period in second language acquisition: The age-attainment geometry

  Frontiers in Physics · 2023-03-20 · 8 citations

  articleOpen access1st authorCorresponding

  One of the most fascinating, consequential, and far-reaching debates that have occurred in second language acquisition research concerns the Critical Period Hypothesis [ 1 ]. Although the hypothesis is generally accepted for first language acquisition, it has been hotly debated on theoretical, methodological, and practical grounds for second language acquisition, fueling studies reporting contradictory findings and setting off competing explanations. The central questions are: Are the observed age effects in ultimate attainment confined to a bounded period, and if they are, are they biologically determined or maturationally constrained? In this article, we take a sui generis , interdisciplinary approach that leverages our understanding of second language acquisition and of physics laws of energy conservation and angular momentum conservation, mathematically deriving the age-attainment geometry. The theoretical lens, termed Energy Conservation Theory for Second Language Acquisition, provides a macroscopic perspective on the second language learning trajectory across the human lifespan.

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Frequent coauthors

• Eun Young Kang

  Kongju National University

  10 shared

• Sarah Sok

  6 shared

• Gang Bao

  Inner Mongolia Normal University

  4 shared

• Lourdes Ortega

  Georgetown University

  3 shared

• Elaine Tarone

  3 shared

• Terence Odlin

  2 shared

• Ashley Beccia

  Columbia University

  2 shared

• Paul J. Wiita

  College of New Jersey

  2 shared

Education

• Ph.D., Applied Linguistics

  Birkbeck College, University of London

• M.A., TESOL

  Moray House School of Education, University of Edinburgh

• B.A., English and English Literature

  Central China Normal University

Awards & honors

• 2003 International TESOL Heinle and Heinle Distinguished Res…
• Teachers College, Columbia University Outstanding Teacher Aw…