ze ze ze ze ze ze ze

When I was randomly watching a music video from the UK on Youtube, when Japanese suddenly showed up on the video like karaoke, which surprised me.
I can learn English by using this.
http://www.youtube.com/watch?v=7XXDM4MmYGQ

You can probably take out the 'which surprised me' because you use 'suddenly' earlier, indicating you weren't expecting it. Including it is not wrong, but it makes the sentence a bit awkward.

That was an interesting video, haha!