Reasons for revitalization vary. In recent times alone, it is estimated that more than 2000 languages have already become extinct. The UN estimates that more than half of the languages spoken today have fewer than 10,000 speakers and that a quarter have fewer than 1,000 speakers and that, unless there are some efforts to maintain them, over the next hundred years most of these will become extinct. These figures are often cited as reasons why language revitalization is necessary to preserve linguistic diversity. Culture and identity are also frequently cited reasons for language revitalization, when a language is perceived as a unique "cultural treasure." A community often sees language as a unique part of their culture, connecting them with their ancestors or with the land, making up an essential part of their history and self-image.