Hebrew seems to be an interesting example as it's claimed to be the only succesful revival. I don't know much about it but it sounds like the community disperse

Hebrew seems to be an interesting example as it's claimed to be the only succesful revival. I don't know much about it but it sounds like the community dispersed to later re-unite and also that the revived language exhibits some discontinuities (which have or will fade with time). The difference between natural and artificial (or constructed) languages is well-defined in linguistics although there may be borderline cases. Again, I don't want to claim that e.g. Hebrew would be somehow tainted as a language now, just that it has endured something very atypical.