The latter have been applied specifically to the problem of estimating word probabilities with sparse additive generative (SAGE) models (Eisenstein et al., 2011), where sparse extra-linguistic effects can influence a word probability in a larger generative setting.
to previous work in which the probability of a word linked to a character is dependent entirely on the character's latent persona, in our model, we see the probability of a word as dependent on: (i) the background likelihood of the word, (ii) the author, so that a word becomes more probable if a particular author tends to use it more, and (iii) the character's persona, so that a word is more probable if appearing with a particular persona.