Table 5.

IGC Showing Group Differences on Rate of Change in Language Measures

	TD vs. ASD-HV (4 Visits)			TD vs. ASD-LV			ASD-HV vs. ASD-LV
	β	SE	T	β	SE	t	β	SE	t
MLU	-0.08	0.10	-0.81	0.37	0.05	7.92**	0.17	0.06	3.00**
Total utterances	-11.98	10.68	-1.12	16.80	5.92	2.84**	3.23	7.03	0.46
Nouns
Verbs	-1.33	2.62	-0.51	9.06	1.31	6.90**	2.35	1.51	2.05
WhIPSyn	-0.50	0.35	-1.44	1.24	0.17	7.16**	0.80	0.20	3.88**
Brown’s 14 morphemes
Progressive	-0.47	0.47	-1.00	0.89	0.22	4.02**	0.80	0.26	3.03**
In				0.25	0.18	1.35	0.07	0.22	0.31
On				0.10	0.10	1.04	0.24	0.12	2.07*
Plural				0.42	0.29	1.44	0.62	0.35	1.77
Past irregular				0.69	0.26	2.67**	0.49	0.31	1.58
Possessives
Uncontractible copula	0.40	0.27	1.49	0.49	0.13	3.81**	0.36	0.15	2.31*
Articlesa	-2.96	1.35	-2.19*	1.35	0.65	2.08*	0.48	0.76	0.63
Past regular	-0.13	0.17	-0.77	0.28	0.08	3.30**	0.28	0.10	2.71**
3rd person singular (-s)	-0.23	0.28	-0.82	0.25	0.14	1.72	0.27	0.17	1.55
3rd person irregular (-s)	0.09	0.15	0.66	0.29	0.07	4.00**	0.11	0.08	1.33
Uncontractible auxiliarya	-0.17	0.08	-2.02*	0.08	0.04	1.96*	0.20	0.05	3.89**
Contractible copula	-0.98	0.65	-1.50	1.25	0.32	3.83**	0.16	0.38	0.42
Contractible auxiliary	-0.64	0.53	-1.21	1.06	0.23	4.57**	0.74	0.27	2.67**

^**<.01,

^*<.05

^aNegative signs indicate measures where growth was faster for ASD-HV group compared to TD group Empty cells indicate that unconditional growth model is non-significant