Table 1.

Characteristics of Included Reports

				Effect Sizes
Reference	Pub	Mean age at T1 (m)	n	Total	Long (Time)	Conc	Cons	Com/Non	ES
Independent Samples			161	14
Cardona (2004)	No	28.60	20	4	4(17)	0	4	4	0.42
Kim (2008)	Yes	48.00	27	1	1(N/A)	0	0	0	−0.11
Paul et al. (2008)	Yes	21.80	37	1	1(25)	0	1	1	‡*0.41
Sheinkopf et al. (2000)	Yes	44.67	15	3	0	3	1	0	0.41
Sigman & Ungerer (1984)	Yes	51.70	16	1	0	1	0	0	0.72
Talbott (2014)	No	8.93	6	2	2(3)	0	1	0	0.54
Yoder et al., 2013	Yes	38.60	40	2	0	2	0	0	0.74
Shared Samples
FIRST WORDS® Project			114	42					0.30
Book (2009)	No	21.98	45	1	0	1	1	1	0.57
McCoy (2013)	No	19.83	114	4	2(12)	2	4	4	ˆ0.52
Plumb (2008)	No	21.29	50	22	22(18)	0	1	2/3	‡0.19
Plumb & Wetherby (2013)	Yes	21.29	50	4	4(18)	0	0	4	‡0.26
Shumway & Wetherby (2009)	Yes	21.29	40	3	3(18)	0	0	3	‡0.43
Swineford (2011)	No	19.80	74	3	1(16)	2	0	3	0.12
Wetherby et al. (2007)	Yes	21.36	42–64	5	4(16)	1	5	5	ˆ‡0.55
Sample from Yoder, Watson, et al. (2015)			87	53					0.55
Woynaroski (2014)	No	39.67	33	8	4(4)	4	4	4	‡0.56
Woynaroski et al. (2017)	Yes	37.90	20	5	5(4)	0	1	1	0.45
Yoder, Watson, et al. (2015)	Yes	34.70	87	1	1(16)	0	1	1	‡*0.40
Yoder, Woynaroski, et al. (2015)	No	25.00	20	15	15(4)	0	1	0	0.26
Yoder et al. (2016)	No	42.13	62–68	24	16(4–12)	8	24	24	0.70
Total		46.16	362	109	85(11)	24	49	57/3

Note.

^ˆ= For at least one effect size, the sign has been changed to reflect increased frequency of vocalizations being associated with higher language skills to be consistent with other effect sizes;

^‡= Partial r for at least one effect size.

^*= At least one effect size originally not reported as r or partial r. Com/Non = Communicative vocalization effects sizes/noncommunicative effect sizes; Conc = Concurrent; Cons = Consonant-centric; ES = unweighted mean effect size (r); Long = Longitudinal; m = Months; n = Average number of participants per effect size; N/A = Not applicable; Pub = Publication status; T1 = Time 1/time of vocalization measure; Time = Average time between vocalization and language measures in months.