My opinion

3 : Why are the Chinese learning English – why isn’t the rest of the world learning Chinese?

I think English is very powerful language in this world economy, politics, and so on.
So people learning English. China has power but Chinese has power smaller than English any plase. It's the reason that the rest of the world people don't learn Chinese.

4 : How difficult woukd you find it to learn a language with a different alphabet and way of writing.

We have listened language that mother language since we were born. However, we haven't listened a language with a different alphabet when we had be 13 years old. We should listen it as many times as possible. Furthermore, we should be used to it.