The Expanded Graded Intergenerational Disruption Scale (EGIDS) provides a measure of a language’s sustainability. This scale, proposed by Lewis and Simons (2010), is an expansion of the Graded Intergenerational Disruption Scale (GIDS) first outlined by Joshua Fishman in his influential book, Reversing Language Shift (Fishman 1991). The thirteen-level EGIDS scale is designed to allow any language—from international to extinct—to be rated.
Summary definitions of the 13 levels are presented in the following table. The unusual numbering of the scale, indicated in the left column, was intentionally designed to maintain backward compatibility with the original eight-level GIDS (original levels 6 and 8 were split, while entirely new levels 0, 9 and 10 were added).
|0||International||The language is used internationally for a broad range of functions.|
|1||National||The language is used in education, work, mass media and government at the nationwide level.|
|2||Regional||The language is used for local and regional mass media and governmental services.|
|3||Trade||The language is used for local and regional work by both insiders and outsiders.|
|4||Educational||Literacy in the language is being transmitted through a system of public education.|
|5||Written||The language is used orally by all generations and is effectively used in written form in parts of the community.|
|6a||Vigorous||The language is used orally by all generations and is being learned by children as their first language.|
|6b||Threatened||The language is used orally by all generations but only some of the child-bearing generation are transmitting it to their children.|
|7||Shifting||The child-bearing generation knows the language well enough to use it among themselves but none are transmitting it to their children.|
|8a||Moribund||The only remaining active speakers of the language are members of the grandparent generation.|
|8b||Nearly Extinct||The only remaining speakers of the language are members of the grandparent generation or older who have little opportunity to use the language.|
|9||Dormant||The language serves as a remainder of heritage identity for an ethnic community. No one has more than symbolic proficiency.|
|10||Extinct||No one retains a sense of ethnic identity associated with the language, even for symbolic purposes.|
In addition, the EDIGS level assigned to a language is in turn rated for how reliable that estimate is. For example, an estimate based on recent, in-depth field work is likely to be highly reliable. At other times, an estimate may be a ‘best guess’ based on general knowledge about an area. More about reliability ratings can be found here.
Fishman, J. A. 1991. Reversing language shift. Clevedon: Multilingual Matters.
Lewis, M. Paul; and Gary F. Simons. 2010. Assessing endangerment: Expanding Fishman’s GIDS. Revue Roumaine de Linguistique 55(2):103–120.