Table 2.

Summary of included acoustic and kinematic subsystem measures

Speech subsystem	Measure	Experimental Task	Procedures
Respiratory	Percent pause time (%) (PPT)	Reading of Bamboo passage	Pauses > 300ms were identified using a custom MATLAB program, Speech Pause Analysis (SPA)*; PPT= total pause duration/total passage duration ×100
Phonatory	Max F0 (Hz)	‘high pitch’ phonation of /a/	Participants raised their pitch from a normal level to the highest pitch possible while vocalizing /a/, and held the high pitch for 5 seconds. Multi-dimensional Voice Profile (MDVP, Model 5105) software was used to measure the maximum pitch obtained during the sustained vowel.
Resonatory	Nasalance (%)	Sentence repetition ‘Buy Bobby a puppy’	KAYPentax, Model 6400 nasometer was used to measure nasalance during sentence production.
Articulatory	Max velocity (mm/s) of UL_LL	Sentence repetition ‘Buy Bobby a puppy’	3D optical motion capture system (Motion Analysis Corp.) tracked movement of reflective markers on each participant’s face; maximum velocity of relative movement between the upper and lower lips was calculated using SMASH (38)
	DDK rate (syll/sec)	Repeat/ta/as quickly and clearly as possible on one breath	DDK rate = # syllable repetitions/total duration (seconds)
	Articulation rate	Reading of Bamboo passage	Articulation rate = # words produced/total speech duration of passage (excluding pauses > 300ms)
System-level	Intelligibility	Reading 10 randomly generated sentences (5–15 words in length) from the Speech Intelligibility Test	Each participant’s speech sample was transcribed orthographically by one naive listener. Intelligibility = % words correctly identified
	Speaking rate (wpm)		Speaking rate = # words produced/total duration (min)