It's Let It Go in 25 languages (I assume these were all the languages the film was released in) with many talented singers. Some of the singers, amusingly, look nothing like you'd imagine a Disney singer to look - I'm thinking of the Danish singer.
I'm a little bit of a language nut, and if you are too, I highly recommend Language: The Basics, by RL Trask. It's a fascinating primer on linguistics and languages. GoodReads