"To adjust playback speed if you're using the Chrome browser, click the Settings icon in the lower-right corner of the playback window, then click the Speed selector. Choose 0.25 for quarter-speed playback or 0.5 for half-speed. (Obviously you can also opt for faster playback if you wish.)
Don't see that option? While I found it in Google Chrome, it wasn't visible in either Firefox or Internet Explorer. However, you should still be able to access it in those browsers by enabling the HTML5 version of YouTube's video player (click "Request the HTML5 player"), or by using the site discussed below."
Yes, there is an option in the settings. However, the option may not always be available depending on platform. To check, go to “settings” at the bottom right of the playback windows (the little gear thing). You should see an option for speed that will allow you to both adjust playback speed either faster or slower.