Can a dying language be revived? John McWhorter mentions “Hebrew, which by the late 1800s had essentially been used only in writing and for liturgical purposes for more than two thousand years … The movement to make it the official language of Israel was so successful that today it is spoken natively by a nation of six million people.” That happy story of reviving the undead has given heart to speakers (& wannabe speakers) of many other dwindling languages. There are serious efforts to bring back to dinner table chitchat such languages as Irish Gaelic, Breton, Occitan, Maori, Hawaiian, and (noted previously) Pomo.
When you’re talking about “a language”, however, you are actually talking about a cluster of dialects, more and less intelligible to each other. When there are so few speakers that this diversity is no longer sustainable the language that is being revived is a language that never really existed. What is taught as the language is a compromise among dialects, an invented standard. Invented languages don’t feel real. You can produce the words for school but when relaxing around the dinnertable they don’t just pop out. Is a language you don’t live in truly alive even if it retains a decipherable existence?
“Because it is harder for adults to learn new languages well than it is for children,” McWhorter continues, “when adults are forced to learn a new language quickly, the result is often various forms of pidginization, utilizing just the bare bones of a language. This becomes a problem in revival efforts because, even when adults of a given nationality desire strongly to have their ethnic language restored to them, the mundane realities of a busy life can make it difficult to get beyond pidgin-level competence in the language.”
Minority languages are some of the most complex on the planet. English is relatively simple. You can say English is in a constant state of pidginization - because learning it is important to non-native speakers English does not have opportunity to become isolated (and thus gather what McWhorter calls “baubles”). “[L]iving languages are developed far beyond the the strict necessities of communication and … incomplete learning guarantees that some of these baubles will be stripped away.” Even children, if the language learning is school-based, “typically speak a rather simplified variety”, particularly if it is a minority language and the language most used outside class is entirely other. Elder native speakers may disdain the improper language of the young, “sometimes putting a damper on enthusiasm for the revival itself.”
source: The Power of Babel: a natural history of language, by John McWhorter
see also Zombie Language part I, part II, and part III.