Table 4.

The Rate of Change in Language Measures across 6 Visits (Unconditional Growth Models) for Groups

	ASD-HV			ASD-LV
	β	SE	t	β	SE	t
MLU	0.18	0.04	4.43**	0.01	0.05	0.21
Total utterances	14.44	4.72	3.06**	11.13	4.09	2.72**
Nouns	-2.06	1.10	-1.87	2.80	1.50	1.87
Verbs	3.47	1.21	2.87**	1.11	0.81	1.37
WhIPSyn	0.92	0.18	5.11**	0.12	0.08	1.50
Brown’s 14 Morphemes
Progressive	0.88	0.27	3.18**	0.08	0.07	1.16
In	0.12	0.15	0.79	0.05	0.02	2.12*
On	0.30	0.12	2.52*	0.05	0.04	1.49
Plural	-0.21	0.34	-0.63	0.39	0.13	2.98**
Past irregular	0.31	0.12	2.56*	-0.18	0.36	-0.48
Possessives	-0.04	0.06	-0.63	0.06	0.10	0.62
Uncontractible copula	0.43	0.14	3.10**	0.07	0.06	1.21
Articles	1.34	0.86	1.55	0.85	0.26	3.27**
Past regular	0.28	0.11	2.55*	No changea
3rd person singular (-s)	0.31	0.10	2.98**	0.04	0.03	1.35
3rd person irregular (-s)	0.14	0.08	1.76	0.02	0.01	1.45
Uncontractible auxiliary	0.21	0.06	3.55**	No changea
Contractible copula	0.51	0.30	1.68	0.34	0.13	2.52*
Contractible auxiliary	0.83	0.24	3.43**	0.09	0.04	2.16*

^**<.01,

^*<.05

^aMean = 0 across all time points