I didn't read the full PDF, but at least in the linked article, I think the number of native speakers as a metric penalizes English (and French), making them look more efficient in the graphs. There are about 3x more non-native speakers than native, and vast amounts of training material has been written by them.
You have to read about half of the article before it mentions this, which should have been in the first paragraph:
> The researchers found the energy and accuracy disparity by measuring the amount of energy used by three open-source AI models, Alibaba’s Qwen 3, Google’s Gemma 3, and Meta’s Llama 3.1.
> The researchers found the energy and accuracy disparity by measuring the amount of energy used by three open-source AI models, Alibaba’s Qwen 3, Google’s Gemma 3, and Meta’s Llama 3.1.