Text-related HTML/XHTML markup tags comprise the richest set of all in the standard languages. That's because the original language—HTML—emerged as a way to enrich the structure and organization of text.
HTML came out of academia. What was and still is important to those early developers was the capability of their mostly academic, text-oriented documents to be scanned and read without sacrificing their capability to distribute documents over the Internet to a wide diversity of computer display platforms. (Unicode text is the only universal format on the global Internet.) Multimedia integration is something of an appendage to HTML and XHTML, albeit an important one.
Also, page layout is secondary to structure. We humans visually scan and decide textual relationships and structure based on how it looks; machines can only read encoded markings. Because documents have encoded tags that relate meaning, they lend themselves very well to computer-automated searches and to the recompilation of content—features very important to researchers. It's not so much how something is said as what is being said.
Accordingly, neither HTML nor XHTML is a page-layout language. In fact, given the diversity of user-customizable browsers, as well as the diversity of computer platforms for retrieval and display of electronic documents, all these markup languages strive to accomplish is to advise, not dictate, how the document might look when rendered by the browser. You cannot force the browser to display ...