Table 1.

Description of target participants in three groups of speakers with Speech Motor Delay (SMD) and control participants in two of the three groups. The lower three rows include information on participants in three databases of speakers with typically-developing speech used to standardize measures.

		No. of participants		Age (yrs)		Gender		PCC		PVC
Group	n	SMD	No MSD	M	SD	Male	Female	M	SD	M	SD	Dialect	Speech and Motor Speech Classification
USAa	415	50		5.1	1.7	40	10	71.8	14.3	91.9	6.1	General American	Idiopathic Speech Delay
			341	4.8	1.7	238	103	74.5	12.2	93.6	4.4	General American	Idiopathic Speech Delay and No Motor Speech Disorder
CNDb	346	87		15.4	11.2	49	38	88.6	10.0	96.2	4.7	General American	Eight types of complex neurodevelopmental disorders
			181	11.7	10.6	114	67	92.8	7.0	97.9	2.5	General American	Eight types of complex neurodevelopmental disorders and No Motor Speech Disorder
ALSPACc	156	9		8.8	0.4	*	*	98.5	1.8	99.8	0.4	Bristol, England	Persistent Idiopathic Speech Delay
Reference Databases
USAd	150	–		10.4	4.3	75	75					General American	Typically-developing speakers
CNDe	200	–		21.0	20.2	100	100					General American	Typically-developing speakers
ALSPAC	25	–		8.9	0.4	12	13					Bristol, England	Typically-developing speakers

Note: *These cells contain figures less than 5 and cannot be shown due to risk of loss of anonymity.

ALSPAC = Avon Longitudinal Study of Parent and Children, CND = Complex Neurodevelopmental Disorder, No MSD = No Motor Speech Disorder, PCC = Percentage of Consonants Correct, PVC = Percentage of Vowels Correct.

^a Shriberg, Campbell, et al. (2019).

^b Shriberg, Strand, et al. (2019). The eight types of CND include: 16p11.2 deletion and duplication syndrome; 22q11.2 deletion syndrome; Autism Spectrum Disorder; Down syndrome; fragile X syndrome; Galactosemia; Idiopathic Intellectual Disorder; Severe Traumatic Brain Injury.

^c Wren et al. (2013); Wren et al. (2016).

^d Potter et al. (2012).

^e Potter et al. (2012) and Scheer-Cohen et al. (2013).