Nicaraguan Sign Language emerged among deaf children in Managua schools after a spoken-Spanish/lipreading curriculum failed to teach them

Nicaraguan Sign Language (NSL) arose in the social setting created by Managua's special-education schools. Deaf children who had previously been isolated at home were, for the first time, brought together in numbers. The schools' formal program was oralist — instruction aimed at teaching spoken Spanish and lipreading — and it largely failed to give the children a working language. What succeeded instead was unplanned: the children pooled their individual home-sign gestures into a shared system, developed and transmitted informally in schoolyards, on the streets, and on the buses between home and school rather than through the curriculum.

This founding setting is the causal setup for NSL's scientific significance: a failed language-teaching program inadvertently assembled the population and the conditions under which a language could be observed emerging from zero language exposure, and then systematized by its second cohort of child learners.

[unverified-quant/mechanism — needs primary] The specific founding dates (schools opening around 1977 and expanding through the early Sandinista period), enrollment figures, and the precise causal account of the oralist curriculum's failure rest here only on a Tier 4 encyclopedia source and have not been checked against a primary Kegl or Senghas document. These details need a primary source before they can be treated as load-bearing; the note is held at seedling until then.