Yes we are! There's someone working on Vietnamese [1]. It's a bit blocked on mdbook support [2], but the translation part could start before that's done. Chapters 2, 3, 4, and 6 are effectively "frozen" for print at this point [3] so they'd be the place I'd recommend starting first!

[1] - https://github.com/rust-lang/book/issues/375

[2] - https://github.com/azerupi/mdBook/pull/200

[3] - https://github.com/rust-lang/book/projects/1