Using a subtitle format like .SRT means that you can distribute subtitles for many different languages without distributing a different version of your video for each language. You just need to make separate .SRT subtitle files for every required language, and make those files available on the web.
Its also possible to explore embedding multiple .srt files within the video file itself. This provides the user with the option to choose from among the translations you make available (or to display no subtitles at all) without the need for additional subtitle files. Patent-unencumbered video container formats that support this include Matroska Multimedia Container (MKV) and the Ogg container format.