The ‘utilitarian’ aspect of languages is actually a lot more complicated than is being made out here. While no one can ‘make’ a population speak a certain language if they don’t actually want to, this is not really what the issue is about. For most people, language is very closely bound up with identity, and a lot of people do very much want to continue speaking their language (often along with learning a majority language).
The ‘problems’ that face minority languages are not always disinterest- if that were the case then I would agree with what has been said in this thread. But it’s more complicated. I really see four other major factors in many language deaths are the perceived or real economic uselessness of the language (the utilitarian part), the sanctifying of the language, stigmatisation of the language, and education.
On the sanctifying bit, the linguistic anthropologist Jane Hill has done a lot of really interesting work on the Nahaut languages of Mexico, where a number of older respected members of the community police the language, and really bear down on anyone who doesn’t speak a ‘pure’ form of the language. Spanish loanwords have naturally entered the vocabulary, and have become part of the everyday language- but when people are made to feel guilty about speaking this ‘adulterated’ language, it ceases to be a thing suitable for everyday communication. (The ironic thing about this is that those policing the language are often people who lived most of their working lives in Spanish speaking areas- although they are careful to excise any Spanish words from their vocabulary, their grammar and idiom is much more ‘Spanishified’ than the everyday language they criticise). This is an issue which is hard to do anything about from the outside, but general awareness of this sort of thing always helps (if nothing else, it might make people realise that any linguistic issue like this is a lot more complicated than people think).
As far as the utilitarian part goes, the issue isn’t about whether we can or should ‘make’ people speak a minority language. I see it as a human rights issue about giving people who want to use that language a reasonable chance to do so. Languages are ‘useless’ only if society is built to make them so (often in a very extreme manner), and that can be at least partially changed. Doing things like giving some funding to media, official documents/signage, and sponsorship of literature in the minority language are at least something to think about. This is the sort of thing that has been done in Wales, and judging by the statistical evidence it seems to be working. Non-monetarily, things are harder (getting things done does actually cost money)- I guess ‘awareness’ would be the main thing. And creating an educated (and I don’t necessarily mean formally) enough environment where calling a language a ‘a kind of rural patois, a bonsai idiolect; a way of specifying concepts central to a particular, highly codified way of life’ wouldn’t make it into a respectable news service. There really isn’t a silver bullet to this—@Lance and @rhetorician are right that the social pressures involved are very strong—but it doesn’t mean there’s nothing we can try, and it actually seems that the hardest part is getting those of us (i.e. us and our governments) with the power to try stuff to care.
The way I see it, education is the worst thing that has happened to minority languages. Most educational systems force people to learn hegemonic languages and nothing else. Providing bilingual education isn’t that hard from a pedagogical standpoint- but it does require a shift in thinking about the rights of minority languages. But it is incredible how important of a role the education system plays in making people stop speaking languages both at home and in public. Parents will very often start speaking the dominant language at home to give their kids an edge in school (or even to just make them not fall behind), and this can end all usage of a language very quickly. In my opinion, this is the most urgent area, both because it is the most straightforward (not to say it is simple) measure to take, and because it is directly within the government’s sphere of responsibility. This isn’t asking for some kind of abstract social change, nor is it up to a few activists to make this kind of change. And getting rid of such a strong pressure against the language might well be all that a group of people needs for the language to live.
I think the fact that people often do care about their languages, and are very interested in preserving them, is enough motivation to deal with a little trouble to make space where people don’t ‘have to go out of your way to speak and find others to speak it with’. And a lot of that is on ‘our’ end, so we shouldn’t really just blame it on natural processes (there’s no such thing- language is cultural every step of the way, and the choices and selections that have been made over the millennia are the outcome of cultural interactions and actual choices people have made).
It is inevitable that some of these languages will die. I’m not so much concerned with the loss to humanity or to scholarship- I’m concerned that this is often a real crime against against certain individuals’ and groups’ heritage and identity. It’s not a thing where a language’s ‘time comes’ in these cases (the only way to see that would be to abstract a language too far from its social context), but where the actions taken by some people have consequences on other people. There is responsibility, and power, and it’s only a natural process insofar as any other disenfranchisement of other people is natural. And that means we should take actions to try and allow people to freely create their identity, including continuing to speak their mother tongue.
And one last thing, @basp responded while I was making this post, and I want to point out that the issue isn’t about abstract retention of a fixed form of any language. It’s about letting people who are now speaking a language which is significant to them continue to do so. The fact that this language will, if kept in daily usage, continue to evolve doesn’t actually make the language less significant to people. And abandoning one language for another is not an ‘evolutionary stage’, but an total change in language. The English spoken by a former speaker of a Native American language is not an evolutionary extension of that language.