Multilingual Arbitrage: Optimizing Data Pools to Accelerate Multilingual Progress
Ayomide Odumakinde, Daniel D'souza, Pat Verga, Beyza Ermis, Sara Hooker
TL;DR
The paper tackles the challenge of multilingual model training with a single teacher by introducing multilingual arbitrage, a strategy that routes synthetic data generation across a pool of diverse models to exploit language-specific strengths. The method reframes distillation as an optimization over which teacher to use for each prompt, employing routing methods (fixed, reward-based, and learned) and a teacher pool that includes multilingual, geo-cluster, and monolingual models. Experiments across 15 languages and 9 models show that arbitrage substantially surpasses single-teacher baselines, with reward-based routing achieving up to a 56.5% average win-rate improvement over the best single teacher and mid-resource languages benefiting the most. Beyond open-ended generation, the approach also improves discriminative tasks and yields richer textual characteristics (more tokens, higher lexical diversity, and readable yet more complex text), illustrating the practical value of strategic sampling in multilingual synthetic data generation. The work highlights the potential of LLM ensembles to accelerate multilingual progress and suggests directions for scaling and safety considerations in future work.
Abstract
The use of synthetic data has played a critical role in recent state-of-art breakthroughs. However, overly relying on a single oracle teacher model to generate data has been shown to lead to model collapse and invite propagation of biases. These limitations are particularly evident in multilingual settings, where the absence of a universally effective teacher model that excels across all languages presents significant challenges. In this work, we address these extreme difference by introducing "multilingual arbitrage", which capitalizes on performance variations between multiple models for a given language. To do so, we strategically route samples through a diverse pool of models, each with unique strengths in different languages. Across exhaustive experiments on state-of-art models, our work suggests that arbitrage techniques allow for spectacular gains in performance that far outperform relying on a single teacher. In particular, compared to the best single teacher, we observe gains of up to 56.5% improvement in win rates averaged across all languages when switching to multilingual arbitrage. We observe the most significant gains for the least resourced languages in our pool.
