---
title: "In Nicaraguan Sign Language, the second cohort of child learners made the grammar more systematic than the adults who invented it"
type: "claim"
status: "seedling"
audit_status: "capture-verified"
source_url: "https://pmc.ncbi.nlm.nih.gov/articles/PMC3031518/"
source_title: "Widening the Lens on Language Learning: Language Creation in Deaf Children and Adults in Nicaragua: Commentary on Senghas"
source_author: "Susan Goldin-Meadow"
source_date: "2011-01-01T00:00:00.000Z"
source_quote: "the innovations introduced into NSL by the second cohort came primarily from deaf individuals who entered the deaf community as children, rather than as adults"
source_tier: 2
provenance: "Promotion from 10-inbox/raw/2026-07-09-hop-nicaraguan-sign-language.md, 2026-07-11"
origin: "batch"
derived_from: ["10-inbox/raw/2026-07-09-hop-nicaraguan-sign-language.md"]
writer_model: "claude-opus-4-8"
date_created: "2026-07-11T00:00:00.000Z"
tags: ["linguistics","language-emergence","cognitive-science","nicaragua","sign-language","critical-period"]
audits: ["2026-07-12 claude-opus-4-8"]
---


The most-cited finding from Ann Senghas's studies of Nicaraguan Sign Language
(NSL) is a cohort effect: the grammar of the language became more systematic in
the hands of the generation that inherited it than in the hands of the
generation that created it. Summarizing Senghas, Susan Goldin-Meadow writes that
"the innovations introduced into NSL by the second cohort came primarily from
deaf individuals who entered the deaf community as children, rather than as
adults."

The concrete example is a grammatical device for tracking who does what to whom.
Per Goldin-Meadow's commentary, "Cohort 2 consistently uses a rotated
perspective across sentences when marking who does what to whom. Cohort 1 does
not use this perspective reliably." The founders — the first cohort, who
assembled the shared system out of their individual home-signs — did not
stabilize this device; the children who acquired that emerging system as their
first language did. The regularization tracks *age of entry*, not simply calendar
generation: the systematizers are those who came to the community as children.

The finding is read as evidence for a child-specific language-creating capacity:
grammar is not merely handed down intact but is actively sharpened by young
learners, who impose structure the input did not fully contain. This is the
mechanism behind the broader observation that NSL is a language observed
[[claim-nicaraguan-sign-language-emerged-from-zero-language-exposure|emerging
from zero language exposure]], and it is a real-world instance of the
learner-driven regularization that the
[[claim-iterated-learning-theory-reframes-model-collapse-as-cultural-evolution|iterated-learning]]
framework models as structure surviving a transmission bottleneck.

> [!note] Seek's commentary:
> This is the surprising, quotable core of the whole capture: the generation
> that *didn't* invent the language improved on the generation that did. Worth
> guarding against the tempting overstatement — "children invent grammar adults
> cannot" — when the sourced claim is narrower and mechanism-specific (the
> rotated-perspective device, reliability of use across sentences). — Seek