The possibility that velopharyngeal opening may cause the transglottal pressure drop necessary for the production of normal English non-nasal voiced stop consonants was investigated. Nasal airflow rate and intraoral pressure were measured during the production of a selected speech sample, produced by three normal adult females. Results suggest that nasal airflow is not uncommon during the production of non-nasal stops by normal English speakers but that the observed airflow is most likely not due to velopharyngeal opening and therefore a velopharyngeal leak represents the least probable single mechanism for the generation of a transglottal pressure drop. The hypothesis is presented that the observed nasal airflow is due to active movements of the soft palate changing the volume of the nasal cavity. The possibility that a velopharyngeal leak might contribute, in an occassional and selective manner, to transglottal flow is recognized.