Remark 5 Note that the other terms in the full likelihood also have a non-trivial purpose: (a) the terms ), encourage the model to correctly reconstruct x 1 and x 2 when back-translating from unobserved languages, L 3 and L 4 , and (b) terms P θ (x 3 | x 4 ), P θ (x 4 | x 3 ) enforce consistency between the latent representations.
full likelihood accounts for a combination of agreement, back-translation, and latent consistency.