Youtube launched 1 year and 8 months before being acquired by google.... It's largely semantics to say that what Youtube is today, isn't a direct result of Google's ownership for nearly 20 years now....
From talking to someone that worked at YouTube for 15 years, they still had a lot of core Python code in 2016 that was legacy from the OG company/team and that code needed to be transitioned to follow the Google way of doing things in C++/Go.
I don't think it was distinct enough from the Google culture like Android was at the start of the acquisition but it seems they had leeway to do their own thing.
No concept of language in a user facing way. No filter by language no search by language. On the contrary searches are translated before running and return all languages, videos are dubbed even when you speak the original language, same but with titles being translated etc. Search being shit is kind of on par with being a Google product though. I wonder if they had any language preferences before Google bought them. I don't remember that far back.