As someone who develops multi-lingual web sites, I can tell you this doesn't work.

It should work, but it doesn't. We test with actual users in their home environments, and... people are messy.

- The vast majority of our users accept the default language (English) when setting up their computers, even if they don't speak English.

- In households where the parents are immigrants, very often the children set up the computer, so it's set to English, which is the child's preference, even if the parents don't speak English.

- Poor households often share a phone or a computer, and each person may not speak or prefer the default language that was chosen by the person who set up the computer.

In the idealized world that Silicon Valley imagines where 1 person uses 1 computer with 1 owner and speaks 1 language, it's fine. But in the real world, it's just a mess.