Studies examining articulatory characteristics of pauses have identified language-specific postures of the vocal tract in inter-utterance pauses and different articulatory patterns in grammatical and non-grammatical pauses. Pause postures-specific articulatory movements that occur during pauses at strong prosodic boundaries-have been identified for Greek and German. However, the cognitive function of these articulations has not been examined so far. We start addressing this question by investigating the effect of 1) utterance type and 2) planning on pause posture occurrence and properties in American English. We first examine whether pause postures exist in American English. In an electromagnetic articulometry study, seven participants produced sentences varying in linguistic structure (stress, boundary, sentence type). To determine the presence of pause postures, as well as to lay the groundwork for their future automatic annotation and detection, a Support Vector Machine Classifier was built to identify pause postures. Results show that pause postures exist for all speakers in this study but that the frequency of occurrence is speaker dependent. Across participants, we find that there is a stable relationship between the pause posture and other events (boundary tones and vowels) at prosodic boundaries, parallel to previous work in Greek. We find that the occurrence of pause postures is not systematically related to utterance type. Lastly, pause postures increase in frequency and duration as utterance length increases, suggesting that pause postures are at least partially related to speech planning processes.