Shortly after developers started testing an all-in-one record and publish feature in the YouTube app, they added another experiment that will be useful for those of us who prefer to just watch videos. You are working on a button with which you can change the Language search languages directly on the input screen. If you are multilingual and want to use voice search, this way you can search for videos that are not available in the language you set up in your YouTube app settings.
Google hopes the test will help its voice search systems better consider multilingual people. So I wouldn't be surprised if an automatic solution to recognize different languages is the ultimate goal. Finally, I still think that Google should work to improve the current language bilingual solutions.
A blue banner with further details should appear on this screen when you participate in the experiment.
As with all of these experiments, the feature is also provided to a small subset of users. You should see a blue banner on the voice input screen that gives you more details when you take the test. According to YouTube, the selector is available for all languages listed on this website, with the addition of Uzbek, Punjabi, Burmese and Estonian. It is still unclear whether you need to scroll through a list of all of these languages when switching, or whether your most commonly used ones are readily available