Portrait of Yilong Wang

Yilong Wang

Student researcher · TU Berlin

Interpretability · multilingual NLP · counterfactual explanations

About

I am a master's student in computer science at TU Berlin, supervised by Qianli Wang. I wrote my bachelor's thesis with Qianli Wang and Nils Feldhus.

My recent research focuses on the interpretability of multilingual language models: whether a concept is represented consistently across languages, and what a model actually relies on when it makes a prediction. Much of my work uses counterfactual explanations, minimal edits to an input that flip a model's prediction. My recent papers improve self-generated counterfactuals through preference optimization in the multilingual setting and through iterative feedback at inference time.

Looking for internship and PhD positions starting in 2027. Feel free to reach out by email.

Recently

  • Two papers were accepted to Findings of EMNLP 2026.

  • Completed my contribution to Apache SystemDS.

  • One paper on multilingual counterfactual explanations is in submission.

  • One paper on counterfactual generation is in submission.

Research interests

  • Multilingual NLP

    Whether a concept lives in the same place inside a model, no matter which language asks for it.

  • Interpretability

    Pulling a dense representation apart into sparse, individually legible features, most often with a sparse autoencoder.

  • Counterfactuals

    The smallest edit that flips a prediction, and everything that edit gives away.

  • On-policy distillation

    Teaching a small model on the trajectories it actually walks, rather than the ones its teacher would have.

  • Reinforcement learning

    A reward is a rough map. Someone still has to walk the route.

  • Memory

    What a model should carry between turns, and what it is better off forgetting.

  • Modality priors

    Every modality arrives already holding assumptions about what it is looking at.

Publications

Findings of EMNLP 2026

iFlip: Iterative Feedback-driven Counterfactual Example Refinement

Yilong Wang*, Qianli Wang*, Nils Feldhus * equal contribution

From the abstract

Counterfactual examples are minimal edits to an input that alter a model's prediction. They are widely employed in explainable AI to probe model behavior and in natural language processing (NLP) to augment training data. […]

arXiv ↗

Coursework

TU Berlin · course report

Sentiment Analysis of Financial News Headlines

Yilong Wang*, Linda Li* * equal contribution

From the introduction

Financial sentiment analysis differs from general opinion mining in a fundamental way: sentiment is rarely conveyed through explicit evaluative words […]

Open source

Completed Contributor · May to July 2026

Apache SystemDS

I contributed to LLM-assisted generation of data augmentation pipelines, building a harness that compared published augmentation baselines against LLM-generated strategies across datasets of different modalities.