1. Navigate to your steamsteamappscommondota 2 betadota directory (might be commondota 2dota instead)
2. Take the contents of the Scripts/voscripts and place in it the corresponding folder in your dota directory. (steamsteamappscommondota 2 betadotaScriptsvoscripts)
3. Do the same with the Sound/Vo and place the folder in it's corresponding directory. (steamsteamappscommondota 2 betadotaSoundvo)
4. Open the properties of Dota 2 in your Steam library, click Set Launch Options, and add -override_vpk
5. Play Dota 2 normally and enjoy!