Multi-track audio is allows the video to have two or more audio tracks that can be chosen by the viewer during playback.
Yes, multi-track audio does work in IE11.
There is an exception, however. Vidyard requires playback with HLS in order for multi-track audio to work. If you are using IE11 on a Windows 7 operating system, the Vidyard must load with a special Flash-supported player that does not support HLS. As a result, multi-track audio will not work.
Learn more about the Vidyard player and browser compatibility.