Table 2.

Acoustic characteristics: Mean fundamental frequency (F0) in Hz, F0 range (Hz), and sentence durations (s) of infant-directed speech (IDS) and adult-directed speech (ADS) stimuli for each speaker.

Speaker	Measures	Type	Sentences
			1	2	3	4
1	F0	IDS	288	322	334	346
		ADS	176	197	192	193
	F0 range	IDS	172–521	168–498	222–523	203–506
		ADS	161–225	171–231	155–218	171–248
	Duration	IDS	1.07	1.52	1.34	1.67
		ADS	0.77	1.03	0.82	0.94
2	F0	IDS	284	229	291	307
		ADS	176	203	208	182
	F0 range	IDS	143–523	131–508	158–439	214–501
		ADS	155–242	75–274	141–262	115–291
	Duration	IDS	0.84	1.40	1.25	1.63
		ADS	0.57	0.86	0.68	1.00
3	F0	IDS	311	229	199	261
		ADS	210	228	209	188
	F0 range	IDS	139–442	151–512	147–511	174–496
		ADS	191–246	143–320	140–312	122–268
	Duration	IDS	0.97	1.15	1.41	1.57
		ADS	0.61	0.77	0.70	0.95
4	F0	IDS	274	221	246	275
		ADS	224	211	225	222
	F0 range	IDS	163–525	142–422	165–313	184–426
		ADS	191–311	76–329	83–268	186–286
	Duration	IDS	1.50	2.31	2.05	1.87
		ADS	0.82	0.95	0.78	1.08