I need to add variable speed to videos on an educational site I am building. 

Users are going to be watching language teaching tutorials and need to have ability to slow playback down in order to clearly hear pronunciation.

In HTML5 there is a playbackRate option that could be adjusted via JavaScript and I was wandering if implementation is possible.

I came accross some of the implementation suggestions (below) but I'm not sure where to try to apply them....

msdn.microsoft.com/en-us/library/ie/hh924823(v=vs.85).aspx
msdn.microsoft.com/en-us/library/ie/ff974757(v=vs.85).aspx

Help is appreciated!