In recent research (full paper also available), researchers from the Google Brain and Google Translate teams have shown intriguing evidence of a so-called interlingua, that is, a language-agnostic common representation of sentences with the same meaning from different languages.
What I also found interesting about this work (and related to the above finding), is that they’re able to perform translations between language pairs that the system has never trained on.
A further pleasant surprise was seeing how they used the t-SNE visualization technique to embed the high-dimensionally represented sentences in 2D, in order to study the interlingua phenomenon.