I personally think that English is the first one. Although most of the content on Hacker News is in English, there is also a small portion of content in other languages, and it would be great if AI could handle that.

In addition, providing AI-powered Hacker News translations and AI summaries in corresponding languages for users using other languages would definitely be attractive, such as French, Chinese, Spanish, and so on. In my personal experience, AI is also very good at these languages, and perhaps starting with them would be a good choice :)

By the way, what is the story about default theme, why it's not follow the system by default? Just curious.