You can control the SPEED in youtube

One of the most valuable option in youtube of today is the speed control: You can decide if it goes slower than normal or speed up your video. 

Here you have the control button:

If this option is not available at your youtube window you maybe are missing the add-on called HTML5 . All things remain the same on your youtube window but you just get the control button!

Place your cursor on the youtube window and RIGHT click. This click brings up a list of options and you take the HTML line. 

I use the slower options when I need to check details but the fast variants are really useful for speeches - at 1.5 you still understand the words but get through a 15 mins speech in 10 mins - GREAT  i think!

(I am updating all my channels with this info - sorry if you are hit by this several times. . .)