1. A system for enabling in-context authoring of substitute content for one or more non-textual objects, comprising: a memory to access an electronic document comprising content data that includes sentences and at least one non-textual object contextually placed in a first position within the sentences; and an authoring environment that facilitates in-context editing of substitute content corresponding to the at least one non-textual object, comprising: an interactive output interface that presents the substitute content positioned in the first position within the sentences and presents at least a portion of the sentences positioned adjacent to the first position to enable a user to contextually review the substitute content with respect to the sentences; and an interactive input interface that enables a user to edit the substitute content positioned within the first position in response to editing commands and enables the user to store the substitute content to the electronic document.
7. A system according to claim 1 , wherein at least one item selected from the group comprising a blank space, marker, text message and icon is presented in lieu of the substitute content if the substitute content for the at least one non-textual object is unavailable.