Sure that’s what you use to talk about particle physics, but this is targeted towards kids and by doing this the “Organisation européenne pour la recherche nucléaire” makes it harder for French, Swiss, German etc. kids to follow.
It should not be hard to do a voiceover, at 4h I’d even volunteer.
But seriously, it's obviously meant to have a wider audience than just those countries you mentioned. Not even mentioning the elephant in the room that they are funded by many other eu countries (~23) that have their own languages as well. What else besides the most international language in the world should they have chosen?
I just wish that for non English speaking kids there would be more resources in their native languages, especially since mathematical interests and interest in languages rarely are equally strong.
The fact that the US has such a large unified one language market really gives them an edge when it comes to creating content.
It would be stupid to ask American educators to provide content in language irrelevant in their country; but given that France, Italy and Germany together provide for 40% of cern budget wishing for human made subtitles surly is nothing outrageous.
For kids below 16 ... I agree. My 7 y.o. is studing some English at school and sometimes she watchs cartoons in English, and she aparently understand most of it. But watching technical stuff is more difficult.