Table 1.

Definition of global endangerment (GE) scores for language endangerment. GE is a conversion of the EGIDS endangerment scale that parallels Isaac’s conversion of the IUCN Red List, in which increases of one unit in GE represent a doubling in the probability of extinction. The age of youngest users is the most important criterion for the EGIDS scale (details in electronic supplementary material, table S1).

GE	EGIDS endangerment	youngest users	other criteria
4	nearly ext.	grandparents	rarely used
3.5	moribund	grandparents	—
3	shifting	parents	—
2	threatened	children	losing users
1	vigorous	children	stable user base
$\frac{1}{2}$	developing	children	standardized lit.
$\frac{1}{4}$	educational	children	used in schools
$\frac{1}{8}$	wider Comm.	children	used in mass media
$\frac{1}{16}$	provincial	children	local govt. lang.
$\frac{1}{32}$	national	children	national govt. lang.