Spontaneous cries of a male infant were recorded daily from birth until the age of 8 weeks. Additionally the parents kept a diary reporting the behaviour and the development of the child. Characteristic sounds for each day were investigated using spectrograms and fundamental (melody) analysis. Also changes in the type of melody, mean values of the fundamental frequency, Jitter, perturbation quotients and the occurrence of noisy components were analysed. The data obtained enabled us to locate behavioural as well as prespeech developmental processes in time. Developmental steps, e.g. transition and regression-phases were described for the first 8 weeks of life. Comparing the behavioural reports to the results of the sound analysis a synchronisation was found concerning the manifestation of developmental steps.