The present study reports the findings of a study that analyzed the use of formulaic sequences in an NNS corpus (i.e., EFL teaching demonstration data) and an NS corpus (i.e., MICASE data). In order to investigate the structural and functional aspects of formulaic expressions in English, the most frequent 4-word formulaic expressions were identified and classified both structurally and functionally. The result of the analysis demonstrates Korean EFL learners’ overuse of the formulaic sequences. In other words, the repeated use of the formulaic sequences resulted in the high frequency of formulaic sequences in the learners’ data. The analysis of formulaic sequences by the structural subcategories shows the high frequency of the clausal expressions, which is one of the major characteristics of spoken discourse. The present study also reports the results of the functional analysis of the formulaic sequences, which indicate that both native speakers and learners mainly employed formulaic sequences to express epistemic and modality stance.