Separate elements
To use two separate elements to support your bilingual application, you declare two separate elements in the DTD: one for each language (called english and french for this example). The language elements would be contained in parent elements with the content model (english, french). This makes both elements mandatory and not repeatable within that container element. It also means that the english element must be before the french element.
The element structure for this method looks like this:
<title>
<english>My Chapter</english>
<french>Mon Chapitre</french>
</title>
The title is the container element. In it are the two language-specific elements: english and french . The DTD forces both elements to exist within their container element.
The FOSI requires that the data to be printed side by side be in one document. But you can still author in two separate documents with separate DTDs. You can develop a merging process to load the two documents' contents into one document with a DTD like the one just described for the publishing and printing process.