1. A system for automatically marking a document to be read by a text-to-speech reader with voice type identifiers, said system comprising: at least one processor programmed to: identify two or more voice types available to the text-to-speech reader, each voice type having a corresponding voice type identifier; identify text elements within the document by marking gross structural subdivisions of text with a first set of sequenced tags, marking individual paragraphs of the text with a second set of sequenced tags, and marking text elements with a third set of sequenced tags to generate a hierarchical tree identifying the text elements; group similar text elements together 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; classify the grouped text elements according to voice types available to the text-to-speech reader; and mark the classified grouped text elements within the document with corresponding voice type identifiers.