1. A computer implemented method, comprising: receiving a user-based selection of a first portion of words in a document, at least of portion of the document being displayed on a user interface on a display device, the document being pre-associated with a first voice model; applying, by the one or more computers, in response to the user-based selection of the first portion of words, a first set of indicia to the user-selected first portion of words in the document; and overwriting the association of the first voice model, by the one or more computers, with a second voice model for the first portion of words.