don't know if this has been mentioned already but the UK are very strict and getting more so, on immigrants "fitting into" England
before you're granted permanent citizenship you have to prove you can speak english either by certificate or taking a test AND you now have to take and pass whats called the "life in the UK" test before you can apply.
its all about making sure people understand what living in the UK is about and integrating properly and so includes such "valuable" questions like "what do you do if you accidently knock over someones pint in a bar?" with multiple choice answers that range from logical to absurd
i don't personally have an issue with expecting people who hope to settle in a specific language speaking country to learn that language - if i wanted to live in France i'd expect to need to learn french
should it be a forced requirement of a visa...? well not a temporary visa but i think if people are applying to settle in a country permanently then once again its not unreasonable to expect that, if they plan on taking the benfits of citizenship and presumably contributing to that country, that they at least speak its language.
worth bearing in mind with that is that it takes years of residence to apply for permanent citizenship - at least 5 years in the UK (except for rare circumstance) where you had to have a visa to start with - and after 5 years of living in a country one should know the language.
if they dont then its reasonable for the powers that be to question what benefit this person is going to bring by joining the country if they can't even contribute on the most basic level
this is especailly prevailant in england where citizens can claim all sorts of things off the government and non-citizens can't - if you're going to be using the country to your benefit then i think you should also be contributing back to the country and speaking the language is obviously a core requirement for this.
but once again, thats only really for permanent visas - if you were planning on going to a country to spend time there and see what its like - get experience, financial benfit etc - i wouldn't expect or agree with a language being enforced. only really if you decided after several years that you now wanted to make this country your home do i think its fair to enforce an understanding of the local language.
however, i really don't care what language you put your signs in though