At the moment YouTube has know way of knowing the content of your video without you telling them what it is.  Part of this will be through the title and description but there is a more powerful tool you can use.

By adding subtitles to your video you are letting YouTube know about every word that is said.  Not only that but you are also making your content more accessible to your viewers who are more hard of hearing. And best of all, it is really easy to do.