Common phrases, not fancy words, can make you sound more fluent in a foreign language

Language learners often assume that using rare, complex vocabulary will make their speech sound more fluent. Research suggests that there is a close relationship between formulaic expression usage in speech and acoustic features of oral fluency. This implies that using formulaic expressions leads to faster articulation speed and fewer disruptions during speech. However, in terms of how listeners perceive speakers' fluency, the role of formulaic expressions has been unclear.