Yong Zheng-Xin

Current: Computer Science Ph.D. @ Brown University
Past: Research Scientist Intern @ Meta AI, Research Collaborator @ Cohere Labs

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I am a fourth-year Ph.D. student in Computer Science at Brown University, advised by Prof. Stephen Bach. I am fortunate to have worked with researchers at Meta GenAI (with Jianfeng Chi), Meta AI FAIR (with Jean Maillard and Michael Auli), and Cohere Labs (with Julia Kreutzer, Beyza Ermis, Marzieh Fadaee, and Sara Hooker).

I work on generalization of post-training to make models more capable and safe, often using cross-language phenomena as scientific lens to reveal core principles of how LLMs generalize to out-of-distribution languages, domains, and tasks. I was a main contributor to T0/mT0 and Aya, and I discovered crosslingual jailbreaks and crosslingual test-time thinking.

My research interests and past work include:

Generalization of reasoning and test-time thinking. I investigated how test-time scaling of English math reasoning models generalizes to other languages and domains. My most recent work shows successful crosslingual generalization due to the "quote-and-think" pattern, but limited cross-domain transfer (preprint).
Generalization of safety alignment I discovered low-resource languages can jailbreak GPT-4 (⭑Best Paper Award, NeurIPS 2023 Socially Responsible Language Modeling Workshop), revealing core limitations in how alignment training interacts with multilingual representations. This work became the seminal work for multilingual red-teaming and has shaped safety frameworks at major AI developers including OpenAI, Meta, and Microsoft. The work was also highlighted in the first International Scientific Report on the Safety of Advanced AI (2024) and featured on New Scientist.
I also used mechanistic interpretability to explain crosslingual detoxification (EMNLP 2024 Findings) and crosslingual finetuning attacks (NAACL 2025 Findings).
Generalization of instruction-following. I was the co-first author of the open-source Aya model (⭑Best Paper Award, ACL 2024) and a core contributor to foundational instruction-following models T0 (ICLR 2022 Spotlight, ACL 2022 Demo) and mT0 (ACL 2023). These work demonstrated that models can learn generalizable instruction-following patterns that transfer across linguistic boundaries.
Efficient adaptation to unseen languages and speech accents: I investigated how pretrained models can efficiently generalize to unseen languages through language adaptation (ACL 2023) and synthetic data (EMNLP 2024 Findings), contributing to mid-training methodologies. I also studied speech pattern distributions across accent groups to enable automatic speech recognition (ASR) models to generalize to unseen speech accents (INTERSPEECH 2025).

featured work (see all)

  1. Zheng-Xin Yong ,  M. Farid Adilazuarda ,  Jonibek Mansurov , and 7 more authors
    arxiv preprint, 2025
  2. Ahmet Üstün* ,  Viraat Aryabumi* ,  Zheng-Xin Yong* , and 14 more authors
    ACL, 2024 (Best Paper Award)
  3. Zheng-Xin Yong ,  Cristina Menghini ,  and  Stephen Bach
    NeurIPS Workshop: Socially Responsible Language Modelling Research (SoLaR) , 2023 (Best Paper Award)

news

05 / 2025 Gave an invited talk at MilaNLP lab.
05 / 2025 1 paper accepted! Work on mitigating accent bias in ASR was accepted to INTERSPEECH’25.
Work was done during Meta internship.
02 / 2025 1 paper accepted! Work on cross-lingual finetuning attacks was accepted to NAACL’25 findings.
Work was done during Meta internship.
09 / 2024 4 papers accepted! LexC-Gen, SEACrowd, and crosslingual alignment were accepted to EMNLP. CVQA was accepted to NeurIPS.
08 / 2024 Aya Model paper received the ⭑Best Paper Award at ACL 2024.
07 / 2024 Gave an invited talk at London Data Week.
06 / 2024 Started research scientist internship at Meta AI (FAIR)!
05 / 2024 1 paper accepted! A Safe Harbor for AI Evaluation and Red Teaming is accepted to ICML.
02 / 2024 Released Aya model and dataset papers!
I also presented Aya multilingual safety research at Aya Grand Finale.
11 / 2023 Co-organized the tutorial on current status of NLP in South East Asia at AACL 2023.
10 / 2023 Low-Resource Languages Jailbreak GPT-4” received the ⭑Best Paper Award at NeurIPS 2023 Socially Responsible Language Modeling (SoLaR) workshop.
09 / 2023 Joined the Cohere For AI’s Responsible Deployment Team for Aya red-teaming.
08 / 2023 Served as the Area Chair (Multilingualism & Linguistic Diversity Track in EMNLP 2023).
05 / 2023 Media: Our code-switching paper was featured by Wired.
05 / 2023 3 papers accepted! BLOOM+1, BLOOMZ and code-switching survey were accepted to ACL 2023.
03 / 2022 2 papers accepted! T0 was accepted to ICLR (Spotlight). PromptSource was accepted to ACL Demo.
06 / 2021 Started PhD at Brown University.

miscellaneous

  • I am a Malaysian 🇲🇾 and I contributed substantially to NLP for South-East Asian (SEA) languages. For instance, I studied language-mixing behaviors for SEA languages (EMNLP 2023 CALCS, EMNLP 2023 Findings, ACL 2023 Findings), contributed Malaysian cultural data to SEACrowd and CVQA, and co-hosted a tutorial for SEA NLP (AACL 2023).

  • I went to Minerva University during my undergrad so I had the opportunity to travel and live in six different countries for at least four months: United States (San Francisco), South Korea (Seoul), India (Hyderabad), Germany (Berlin), Argentina (Buenos Aires), and United Kingdom (London).

  • One of my biggest passion outside of work is dancing 🕺, especially salsa and bachata. I also dance a bit of Lindy Hop, Argentine Tango and K-pop. I usually check out the dance scenes in the city when I travel to conferences ––– if you also enjoy dancing, hmu we can check them out together.