It appears that Google is testing out a new feature in its YouTube for Android app. Some users are seeing speed controls appear in the app. This is a feature that was not present before, but it was present on the desktop version of YouTube. These speed controls allow you to speed up or slow down videos, and with some YouTubers, it's a good idea to speed up their videos, as they may talk slow or are slow to get to the point of the video. Many people prefer to speed up podcasts, so they can get through an hour-long podcast in about half the time. Which also makes plenty of sense.
Users that are seeing these speed controls on YouTube, are seeing them in the settings menu on a particular video. It appears below closed captioning and above the View in Cardboard listing. Tap on the Speed, and you can choose from slowing it down to 0.25x, 0.50x or 0.75x. You can also speed it up to 1.25x, 1.5x and 2x. Now these aren't controls that everyone uses but they are used by a good amount of people that use YouTube all the time. It's also good to see that YouTube is making its mobile platform a bit more inlined with its desktop experience, so that users are able to have the same experience no matter where they are watching YouTube.
It is important to note here that while YouTube is testing out this feature for a small number of users right now, it doesn't mean the feature will be made available for everyone. It is possible that this will roll out to everyone, seeing as it is a feature that is available on desktop currently, but it is not confirmed. So for now, you'll have to take this with a grain of salt. But if the feature does work okay, and users give good feedback on the feature, it'll likely show up on everyone's version of YouTube. As for now, it's just a small number of users that have the feature, unfortunately. And there's no way to make it show up for you, it's all in Google's hands.