Changing parameters using the query when loading FSI Viewer lets you tweak your presentation easily. Many companies already offer multi-lingual versions of their websites. The visitors native or preferred language can be determined easily by letting the user choose for himself or even automated by evaluating the browsers Accept-Language header or using GeoIP tracking.
No matter which way you chose, we will consider you have determined the preferred setting and have it stored in either a session or cookie. Using server sided scripting, you can easily append the language information to the FSI Viewer query, e.g.
writeFlashCode( "http://demo.fsi-server.com/fsi/viewer/fsi.swf?[other_settings]&language=<?php echo $user_language; ?>", "...", "...");
If you prefer to load a custom configuration file for customers using a certain language (e.g. you offer translated help pages or want to define metric settings for the measure plugin) you can also load a custom .fsi file depending on the value of $language_fsi
writeFlashCode( "http://demo.fsi-server.com/fsi/viewer/fsi.swf?[other_settings]&cfg=<?php echo $language_fsi; ?>", "...", "...");
Please keep in mind that settings in the query will overwrite any settings made in any .fsi files.