It's well known and well documented in AI research.
Instead of taking syntactic shortcuts, the richer abstractions learned from multiple languages, and code, and math, and images and audio, ultimately make English comprehension and reasoning far stronger.
If you want citations, ask your favorite LLM how linguistic diversity prevents "surface memorization", overfitting on surface-level English patterns instead of representing the deeper concepts in latent vector space.
Instead of taking syntactic shortcuts, the richer abstractions learned from multiple languages, and code, and math, and images and audio, ultimately make English comprehension and reasoning far stronger.
If you want citations, ask your favorite LLM how linguistic diversity prevents "surface memorization", overfitting on surface-level English patterns instead of representing the deeper concepts in latent vector space.