During speech perception, neural activity entrains with moments of high acoustic change. For example, periods of high change in speech amplitude envelope magnitude are tracked by neurons in the human superior temporal gyrus. However, it is unknown whether neural entrainment may also be driven by modulation in the articulatory domain. To locate periods of high articulatory change, a spatiotemporal modulation function (Goldstein, 2019) that quantifies change over time in global vocal tract posture can be used to investigate the potential for such entrainment. Here, the frequency patterning and stability of modulation maxima, called “pulses,” are assessed using articulatory point-tracking data. The median frequency of both articulatory and acoustic pulses is found to be only slightly higher than theta band frequencies (6i–8 Hz), at which neural entrainment with speech has been reported. Within- and between-speaker variability of inter-pulse intervals is also compared to the variability of acoustic syllable and acoustic stress foot durations. The results show that intervals between pulses are more stable than syllable and foot durations. In sum, the spatiotemporal modulation function exhibits a stable frequency profile in the articulatory and acoustic domains that could be leveraged in the neurocognitive functions at work in speech perception. [Work supported by the NIH.]