set endpoint language to zh but return me other language news

[ValerieKC]

This is my api request below(api key is hidden for safety concern):
https://api.mediastack.com/v1/news?access_key=${my-api-key}&language=zh

Actually, it's not only language has problem, no matter what I set for end point, this api seems to response me same results, and it looks like the same no matter how I restrict the search parameter.

I'm using a standard plans