TABLE 1.

Summary of demographic information from each corpus

Corpus + location	Language(s)	N	Age (months)	Gender	Maternal education (years)	Avg. dur. (range)
Bergelson, New York, USA	English	10	7–17	4 M 6F	12–22	13.4 h (11.1–16)
Casillas, Chiapas, Mexico	Tseltal	10	2–36	5 M 5F	0–12	9.2 h (8.2–9.6)
Casillas, Milne Bay, Papua New Guinea	Yélî Dnye	10	1–36	5 M 5F	06–14	8.1 h (7.:2–9.2)
Cychosz, Chuquisaca, Bolivia	Spanish + Quechua	3	22–25	3 M OF	06–12	10.4 h (5.4–14.3)
Scaff, Beni, Bolivia	Tsimane′	16	8–32	10 M 6F	0–09	15.6 h (10.9–16)
Warlaumont, California, USA	English + Spanish	3	3	1 M 2F	10–16	12.5 h (10–16)