Objectives: The aim of this prospective study was to measure nasal and oral airflow during speech, before and after obturation. Patients and Methods: Included were children aged 3-18 years with nonsyndromic clefts and palatal fistulae. The corpus used was: syllable /pi/; a sentence containing stop consonants and a nasal phoneme; and the description of a picture of a scene. Analysis criteria were: percentage of nasality; value of average flow for the explosion; perceived nasality and intelligibility; and tolerance of the proposed device. Results: Only 5 children were included due to the observation of an increase in the percentage of nasality after obturation. The value of average flow for the explosion increased in all patients. A decrease in perceived nasality was noted in all but 1 patient. An improvement in intelligibility was observed in 3 out of the 5 children. The tolerance of the device was good. Conclusion: While the small number of patients studied does not permit firm conclusions concerning the efficiency of the obturation, the method described, as well as the introduction of ‘speed of explosion' of stop consonants, offer new perspectives to prospectively study obturator effects on speech.