The behaviors of esophageal speech and tracheoesophageal shunt (TE shunt) speech were compared using two laryngectomized subjects who were able to perform both phonation methods. Through X-ray fluorography and fiberscopic observation of the PE segment, it was confirmed that the location and the shape of the vibrating PE segment (pseudoglottis) were consistent during esophageal speech and TE shunt speech in each patient. It was suggested that the mechanism of formation of the pseudoglottis does not differ between the two phonation methods. The aerodynamics were examined using one of the two subjects. There was a positive relationship between subpseudoglottic pressure and vocal pitch and also between subpseudoglottic pressure and pseudoglottic resistance. The vocal pitch and pseudoglottic resistance were significantly higher in esophageal speech than TE shunt speech, when compared within the same subpseudoglottic pressure range. It was suggested that the tension and the effective mass of the pseudoglottis was modulated differently between the two phonation methods.