1. A system for automatically marking a document to be read by a text-to-speech reader with voice type identifiers, said system comprising: means for identifying two or more voice types available to the text-to-speech reader, each voice type having a corresponding voice type identifier; means for identifying text elements within the document, wherein the means for identifying text elements is configured to mark gross structural subdivisions of text with a first set of sequenced tags, mark individual paragraphs of the text with a second set of sequenced tags, and mark text elements with a third set of sequenced tags to generate a hierarchical tree identifying the text elements; means for grouping similar text elements together, wherein said means groups similar text elements by generating one or more clusters according to each identifiable topic of the document and by syntactically parsing the document and subsequently performing text mining to determine which text elements in the document are similar, wherein similarity is based upon lexical affinities among the text elements; means for classifying the grouped text elements according to voice types available to the text-to-speech reader; and means for marking the classified grouped text elements within the document with corresponding voice type identifiers.