The 18th century Scottish thinker, James Burnett - more often known as Lord Monboddo (1714 - 1799), held both intriguing and eccentric beliefs and is probably best remembered for the idea that orang-utans could speak but chose not to, for fear of being enslaved. That's quite an interesting idea about the power of words.
Until very recently the French chose not to speak English, for fear of being enslaved.
I once took part in a residential international conference at the Centre Culturel at Cérisy la Salle which had a written policy that all proceedings should be conducted in French. One poorly briefed participant got up and indicated that he would give his talk in English, at which point the French simply walked out. I am sure it still happens.
The exception culturelle is still taken very seriously and the continued protection of the use of French very obvious. It is a double edged policy.
On the one hand, a country of fifty million people can perfectly well sustain a culture in which the language of daily life and culture is French and where foreign books are simply translated and foreign films dubbed or sub-titled. In addition, France sustains an Imperial relationship with many of its former colonies around the world and the language of that relationship is French - it was in that language that those colonies were enslaved. No alternatives were permitted (as they were in the Austro Hungarian empire, for instance, and to some degree in the British especially in India).
But protection of the language and culture has its downside even for the metropolitan country. In France, people until recently had to listen to crap pop music because there is a law which said they must. The law is still there but the Internet means it is now less effective - you don't have to listen to rubbish radio stations, you can download the music you want to hear.
And whilst films and novels were done over into French, it didn't happen for academic work - perhaps for the simple reason that there was far too much of it, and all in English. As a result, French universities became backwaters, lagging behind in both science and humanities, and teaching Franco-centric or simply obsolete material. French universities simply did not figure on international rankings and still do not.
Computing and the Internet has become a real challenge for the exception culturelle. The common language of the virtual world is English. There is really only one option: Get Over It. (And I say that as someone whose Mouse Mat - courtesy of The London Review of Books - tells me the Alt numbers I need to produce French accents. Eventually, of course, the accents will disappear as they already do in lots of Internet French).
There are, of course, worse examples than France. When right-wing Nationalists got an independent Ireland, they set about trying to make it Irish Gaelic speaking. Combine that policy with that of a Catholic Church which insisted on Latin, and you got a nasty little clerical-fascist "republic" into which it was a misfortune to be born. You were ruled by people who wanted to isolate you from the world - from modernism, democracy, secularism.
Unlike the imposition of Hebrew as the language of Israel, the imposition of Irish Gaelic never really worked - urban areas like Dublin weren't going to give up English so even if the buses were kitted out with signs which gave their routes in Gaelic, everyone with an ounce of sense was talking English - and reading English-language newspapers. And the universities remained English language institutions.
Irish Gaelic is fine as a hobby, and likewise Scottish Gaelic or Welsh, but as a language of a modern society - well, just forget it. You - and this includes the European Union - do people no favours if you encourage them to stick with a very minority language. For those who are native Welsh speakers, there is a very simple and sound educational policy which can be pursued: Welsh as the language of early years schooling and English as the language of secondary schooling. This is a policy of general applicability. It is one which does not isolate people either from their language of origin or the language they need for adult life. It is very similar to what happens in Scandinavia.