. Author manuscript; available in PMC: 2008 Jun 21.

Published in final edited form as: J Speech Lang Hear Res. 2008 Apr;51(2):423–435. doi: 10.1044/1092-4388(2008/031)

Table 3.

Intraclass correlations for monozygotic and dizygotic twins and univariate estimates of genetic and environmental effects on child language sample measures with effects of age and sex removed.

Child language variable	MZr	DZr	h² (CI)	c² (CI)	e² (CI)
MLU-C	.491^a	.358^a	.48 (.05–.79)	.09 (.00–.42)	.43 (.31–.61)
NTW	.576^a	.342^a	.67 (.32–.89)	.00 (.00–.00)	.33 (.25–.48)
NDW	.531^a	.301^a	.61 (.23–.82)	.00 (.00–.00)	.39 (.29–.55)
D	.351^a	.134	.37 (.00–.56)	.00 (.00–.00)	.63 (.48–.82)
TNC	.384^a	.268^a	.49 (.00–.71)	.00 (.00–.00)	.51 (.38–.74)
DSS	.420^a	.186	.44 (.00–.65)	.00 (.00–.00)	.56 (.40–.76)
SB-Vocab	.467^a	.218	.45 (.00–.64)	.00 (.00–.00)	.55 (.41–73)
BNT	.843^a	.653^a	.43 (.25–.66)	.44 (.20–.69)	.13 (.10–.18)

Note. CI = confidence interval; h² = heritability; c² = shared environmental effects; e² = combination of nonshared environment and error.

Denotes correlations that are significant at an alpha of .008.