Chinese ML researchers primarily publish in English and only secondarily in Chinese. For example, take the Qwen-3.8-Next blog post https://qwen.ai/blog?id=qwen3.8-flash-next (which apparently doesn't include the language choice in the URL, so you'll need to switch to the 简体中文 translation manually). Even in the Chinese version, the "Hugging Face", "Tech Report" and "FlashQLA" links point to English documents, and the ModelScope link has a brief flash of English content before autotranslation kicks in to turn it into Chinese. I'm not sure what is used on the Qwen Discord, but I would guess it's a mix of languages.

Personal communication is of course different from official documentation, but a researcher who wants to establish a working relationship with Chinese colleagues could easily do so while communicating entirely in English.