Syntactic recursion is argued to be a key property of naturallanguages, allowing us to create an infinite number ofutterances from a finite number of words and rules. Somehave argued that recursion is uniquely human. There are atleast two possibilities for the origins of recursion: 1)Recursion is a property of the language faculty. 2) Recursionis an historical accomplishment and is culturally constructedover millennia. Here we ask whether an emerging signlanguage, Nicaraguan Sign Language (NSL), exhibitssyntactic recursion by comparing the language of the firstthree age cohorts of signers. Signers (n=27) watched anddescribed vignettes designed to elicit relative clauses. Resultssuggest that signers from all three cohorts have strategies tofulfill the discourse function of relative clauses, picking outan individual from a set. The grammatical form of theutterances differs across cohorts, with signers from latercohorts clearly producing embedded structures.