it's beyond words: o que isso significa?

Imagine you get a surprise party and then you're out of words, you don't know what to say to those people that could possibly convey what you're feeling right now. So you say:I'm thankful beyond words. I don't know how to thank you.

When you say it's beyond words, you can't find words to say how much thankful or happy you are about something. It's very much about the feeling you're having at the moment. People say that a lo while giving a speech. They wanna show how moved they are by something. It's also a good thing to say when you are literally out of words, and don't know what to say.