He's speaking Dutch and speaking English with a very very heavy west-Netherlands accent. Quite a lot of the Meta employees there can't speak Dutch which is why he switches to English.
I think I should have worded my comment differently. I did not mean the guy does not speak dutch, the video was not playing in dutch because of that shitty auto dubbing of youtube.
Yeah I saw that after posting. I have the same issue, and I'm fluent in Dutch.