This study was conducted to explore the influence of speaking on ventilation. Twenty healthy young men were studied during periods of quiet breathing and prolonged speaking using noninvasive methods to measure chest wall surface motions and expired gas composition. Results indicated that all subjects ventilated more during speaking than during quiet breathing, usually by augmenting both tidal volume and breathing frequency. Ventilation did not change across repeated speaking trials. Quiet breathing was altered from its usual behavior following speaking, often for several minutes. Speaking-related increases in ventilation were found to be strongly correlated with lung volume expenditures per syllable. These findings have clinical implications for the respiratory care practitioner and the speech-language pathologist.