Table 2.

Zero-order fixed effects estimates for vocal variables predicting end point expressive language.

Construct	Vocal variable	Coeff.	SE	t	df	p	Pseudo R 2
Quantity	Number of total vocalizations HC	0.26	0.07	3.74	89	< .001	.16
	AQV A	2.9 × 104	6.8 × 105	4.35	84	< .001	.19
Communicative quality	Number of communication acts with a vocalization HC	0.86	0.10	8.64	86	< .001	.54
	Proportion of communicative vocalizations HC	0.69	0.07	9.35	86	< .001	.59
Phonological quality	DKCC HC	0.59	0.06	9.41	86	< .001	.60
	Proportion of vocalizations with a canonical syllable HC	0.38	0.05	7.26	86	< .001	.44
	ACPU-C+V A	0.27	0.10	2.71	87	.01	.08

Note. See Xu (2003) for pseudo R ² details. Coeff. = unstandardized coefficient; SE = standard error;

^HC = human-coded; AQV = automated quantity of vocalizations (which is the number of child vocalizations);

^A = automated; DKCC = diversity of key consonants used in communication acts (Wetherby et al., 2007; Woynaroski et al., 2017); ACPU-C+V = average count per utterance–consonants + vowels (Woynaroski et al., 2017; Xu et al., 2014).