Translating content

Hello, everyone!

I hope I’m posting this in the right place!
I already have the translation of all of my pages in my blog. I had friends translate them into different languages.
Now, my question is: is there some sort of plugin or something I can use so that my viewers “click” and the translated text shows up without reloading the page (and without making ‘another’ page with the translated content).
I saw this in some European blog sometime ago, but haven’t been able to find it again ever since. The page remained exactly the same, no reloading, but the text just smoothly transitioned to the language selected. It looked somewhat Ajax-y of Flash-y.

Does anyone know how to do this?

Thank you all!