Table 1. Results of the acoustic analysis.

	Chichuru	Chova	Messina	Nuanedi	Shan
Sex	male	male	female	female	female
Age in years	15	17	9	10	13
N rumbles nasal (% separation context)	26 (92%)	13 (77%)	25 (96%)	29 (93%)	22 (100%)
Mean duration ± SD	1.9±1.3	1.4±0.6	2.8±1.5	3.1±1.8	2.8±0.8
Mean F0 ± SD	16.5±1.9	16.7±0.6	19.5±3.2	19.57±2.3	20.5±3.2
Mean F1 ± SD	40.1±4.9	39.5±9.5	45.3±30.7	42.6±7.4	42.0±23.2
Mean F2 ± SD	117.9±11.2	121.6±7.4	140.5±75.8	129±10.1	139.1±89.6
Mean SPL ± SD	52.0±4.7	43.7±8.1	51.1±7.7	53.5±4.8	48.7±6.5
VTL (m)	2.24	2.13	1.84	2.03	1.80
N rumbles oral (%bonding context)	0	0	21 (86%)	21 (72%)	10 (100%)
Mean duration ± SD			1.66±0.8	2.0±1.3	1.2±0.7
Mean F0 ± SD			24.7±4.4	30.2±2.4	22.7±4.8
Mean F1 ± SD			162.1±44.6	162.0±29.8	176.1±16.4
Mean F2 ± SD			381.1±90.1	397.89±20.3	453.1±35.0
SPL ± SD			74.5±10.1	75.6±2.9	69.2±8.4
VTL (m)			0.79	0.74	0.63

The age and the sex of each recorded individual, the number of orally and nasally emitted rumbles (and the percentage of those recorded in each context, respectively), and the mean duration, mean fundamental frequency, mean formant frequency values 1 and 2, and mean sound pressure level (SPL) ± SD of rumbles per individual are presented. The estimated vocal tract length (VTL) for each individual based on the spacing in Hz between formants 1 and 2 for nasal and oral rumbles is also given.