What do MUMBO JUMBO and GIBBERISH mean?

MUMBO JAMBO

meaning: speech or writing that is nonsense or very complicated and cannot be understood 

example: There's so much legal mumbo jumbo in these documents that it's hard to make sense of them.

situation 1:

-Dude, I'm so terrified at the horror movie I watched last night. So you have an idea I tossed and turned the whole night and couldn't get a wink of sleep. I'll never watch a horror movie again.

-What happened in that movie that was so terrifying?

There was this scene in the movie where everybody who whispered some words into a mirror would eventually die a very terrible death. And now I can't even look into a mirror without thinking I might get killed too.

-Are you out of your senses? Everything in the movie was staged in a way it seems real. But don't waste your time fearing such mumbo jumbo.

situation 2:

You're in class watching a Math class. The problem is that the teacher seems to be speaking a different language. You're desperate to understand the littlest things in the class but it seems you'll need to study the basic things first to try to keep up with the level of that class. By the end of the class you meet up with a classmate and then she asks you if you're ready for the upcoming Math tests. Here's what you say:

- I couldn't get half of all that mathematical mumbo jumbo. I'll probably need to do a lot of studying before the test.

GIBBERISH: You can also refer to things that simply do not make sense as gibberish. If someone says you're talking gibberish, they probably mean they can't understand what you're saying. Either because you're maybe speaking too fast and are hard to understand or you're conveying no message. When some people start learning English, they may speak a lot of gibberish in an attempt to get themselves across. That happens because they're still not used to English grammar or vocabulary. One of these days I saw someone saying on Twitter that internet slang is nothing but gibberish.

ASnd speaking of gibberish, here's a video of two babies talking to each other (an Youtube video that went viral and you've probably watched it). That's a great example of what gibberish sounds like.