Although the basic structure of any spoken language is standard throughout the world (word, sentence, paragraph, page), word processing and desktop publishing programs utilize different codes to define the layout within the document. The code that turns bold on in Microsoft Word is different than in WordPerfect. Likewise, the codes that define image placement, page numbers, headers, footers, margins, tabs, font changes and so on are unique to each application. Even more ridiculous is that the code to end a line and paragraph are not the same in Windows and Mac. See line break. Document conversion is accomplished by using import and export filters within the application itself. If a document format is not supported, a separate conversion program is often available. As a last resort if no automatic conversion is available, manual searching and replacing of the layout codes may be possible if the embedded codes can be revealed as ordinary text and both systems follow the same syntax. See standards.