Hi! I’m Kohei Kajikawa, a first-year Ph.D. student in Computational Linguistics at Georgetown, advised by Prof. Ethan G. Wilcox.

My research lies at the intersection of psycholinguistics and computational linguistics. I study how humans comprehend sentences incrementally, that is, how hierarchical, multi-layered linguistic information is processed under cognitive resource constraints. I am also interested in why language structures are the way they are. I investigate the extent to which processing efficiency can, and cannot, account for cross-linguistic syntactic patterns.

Previously, I was at National Institute for Japanese Language and Linguistics (NINJAL), working with Prof. Yusuke Kubota and Prof. Shinnosuke Isono. Before that, I earned my M.A. and B.A. in Linguistics from The University of Tokyo.

• 📄: CV
• ✉️: kk1571 [at] georgetown.edu
• 🔗: [Google Scholar] [Twitter] [GitHub] [ResearchGate] [researchmap]

News

• 08.2025: Started PhD at Georgetown Linguistics.
• 12.2024: Best Paper Award at CoNLL2024.
  → Older news

Publications

Preprints

• Shinnosuke Isono, Kohei Kajikawa, Yohei Oseki, and Masayuki Asahara. Modeling memory effects in a head-final language with category locality. [PsyArXiv]
• Kai Nakaishi, Ryo Yoshida, Kohei Kajikawa, Koji Hukushima, and Yohei Oseki. Rethinking the Relationship between the Power Law and Hierarchical Structures. [arXiv]

Conference Proceedings

• Ryo Yoshida, Shinnosuke Isono, Kohei Kajikawa, Taiga Someya, Yushi Sugimoto, and Yohei Oseki. 2025. If Attention Serves as a Cognitive Model of Human Memory Retrieval, What is the Plausible Memory Representation?. In Proceedings of the 63rd Annual Meeting of the Association for Computational Linguistics (ACL), pp.9795-9812, Vienna, Austria. [pdf]
• Kohei Kajikawa, Yusuke Kubota, and Yohei Oseki. 2024. Is Structure Dependence Shaped for Efficient Communication?: A Case Study on Coordination. In Proceedings of the 28th Conference on Computational Natural Language Learning (CoNLL), pp.291–302, Miami, FL, USA. 🏆Best Paper Award [pdf] [slides] [code]
• Kohei Kajikawa, Ryo Yoshida, and Yohei Oseki. 2024. Dissociating Syntactic Operations via Composition Count. In Proceedings of the 46th Annual Meeting of the Cognitive Science Society (CogSci), pp.297–305, Rotterdam, The Netherlands. [pdf] [slides] [code]
• Shinnosuke Isono, Takuya Hasegawa, Kohei Kajikawa, Koichi Kono, Shiho Nakamura, and Yohei Oseki. 2023. Formalizing Argument Structures with Combinatory Categorial Grammar. Lecture Notes in Computer Science, pp.83–99. [pdf] [slides]

Conference Presentations/Posters

• Shinnosuke Isono and Kohei Kajikawa. 2025, Dec. Grammar as logic, processing as deduction, actions as theorems, states as propositions. Computational Psycholinguistics Meeting 2025 (CPL), Utrecht, The Netherlands. 📣Spotlight poster presentation [abstract] [poster]
• Kohei Kajikawa and Shinnosuke Isono. 2025, Dec. Syntactic Node Count as Index of Predictability. Computational Psycholinguistics Meeting 2025 (CPL), Utrecht, The Netherlands. [abstract] [poster]
• Kohei Kajikawa*, Shinnosuke Isono*, Yushi Sugimoto*, Masayuki Asahara, and Yohei Oseki. 2025, Jul. Exploring spatial and temporal dynamics of language comprehension in the brain with CCG. The 47th Annual Meeting of the Cognitive Science Society (CogSci), San Francisco, CA, USA. (*=equal contribution) [url] [poster]
• Kohei Kajikawa. 2023, Nov. Analyzing Japanese Cleft Construction in Combinatory Categorial Grammar. In Proceedings of Logic and Engineering of Natural Language Semantics 20 (LENLS), pp.99–103, Osaka, Japan. [abstract] [slides]

Awards and Honors

• 06.2025: NINJAL Director’s Award
• 06.2025: NINJAL Young Researcher Encouragement Award
• 12.2024: CoNLL 2024 Best Paper Award

Grants and Fellowships

• 12.2025: Travel Grant for Computational Psycholinguistics Meeting 2025
  • supported by MultiplEYE COST Action
• 12.2025: Travel Grant
  • supported by Department of Linguistics, Georgetown University
• 04.2025 - 03.2028: JSPS Research Fellowship (DC1) [kaken]
  • JPY 200,000/month + JPY 3,900,000 (research grant over 3 yrs)
  • 09.2025: Declined the fellowship upon accepting an offer to pursue doctoral training abroad.

Academic Service

Peer Reviewing

• CoNLL2025 (Outstanding reviewer), LREC2026

Education

• 08.2025 - Present: Ph.D. in Computational Linguistics, Georgetown University
• 04.2025 - 08.2025: Ph.D. in Linguistics, National Institute for Japanese Language and Linguistics (NINJAL)
• 04.2023 - 03.2025: M.A. in Linguistics, The University of Tokyo
• 04.2019 - 03.2023: B.A. in Linguistics (minor in Computer Science), The University of Tokyo