WHat are the differnces between these two expressions ' loosely translated' and' dumb down'?

Loosely translated means they translation isn't an exact translation of what is said, like if someone said "你好!你吃过了吗？你想看一个电影吗?" The real translation is "Hello! Have you eaten? Do you want to watch a movie?" But in Chinese "Have you eaten?" is actually used more like How are you doing? So a loose translation is more like "Hey, how are you doing? Want to watch a movie?" It may not be an exact translation but the ideas and thoughts are contained in the translation anyway.

If you are translating poetry from one language to another it's VERY hard to get the same feeling when translating the words directly, so often you'll see them change the poem slightly to trya nd make it feel better in the new language, it would bea loose translation of the original poem.

Dumbed Down means you've taken something complicated and made it easier for stupid people to understand.

For example one of my friends wanted to buy a Video Card for his computer, there were two cards, one had more ram and a wide variety of newer options. If I had tried to explain them all to him he wouldn't have known what I was talking about so I just said "This one will make the games look better." I dumbed down the information so that a non-Technological person could easily understand it.

If I may add to Dumbed Down.

It can also reference the lack of education. Back when plantation owners kept slaves they would not allow or teach the slaves to read or write. Therefore they were not able to learn to thier highest ability and can be said were kept Dumbed Down.