Some time ago I learned about the uses of で particle and one of them is scope for example:
このマンガは日本で有名です
but now with the uses of 中 says that when it's used after a place indicates the scope of an action in that place, so I found on internet this example:
英語は世界中で話されています
My question is in second sentence, What is the difference of put 中 in relation to the scope? Why not just put で? or if i put 中 in the first what does that involve?