The kymograph, one of the main devices used in early experimental phonetics, was quickly exploited to describe the sounds of languages in sub-Saharan Africa. By 1926, Doke used this device in its phonetics Zulu, to objectify the description of the main sounds of this language: vowels with epiglottal friction; the difference between aspirated and non-aspirated explosive consonants and consonants he describes as ejectives explosives; the three types alveolar laterals (voiced, voiceless and voiceless lateral); the duration of vowels and the different levels of tones. Doke shows that these are the plots of kymograph which to observe a similarity between the consonant bilabial implosive [ɓ] and clicks. The kymograph plots, presented in Figure 1 show indeed clearly a negative airflow at the release of the implosive and of the dental click contrasting with the positive flow observed after a bilabial explosive consonant.