Fig. 3
From: Melodic and articulatory development is delayed in deaf infants aged 2–4 months
Frequency spectra (linear, up to 4 kHz; time representation above) of individual cooing vocalisations. Note that all examples also display the inspiratory noise following the coo. Example (a) displays a vocant (vowel-like vocalisation or ‘quasivowel’), while the other examples show coos with supra-laryngeal activity, well recognisable by the occurrence of consonant-like elements (vertical structures). For the original audio files of these vocalisations see Supplementary Information.
