This research project focuses on identifying what types of speech acts emerge and are maintained in the teacher-student interactions in an EFL Pre-intermediate class at university level. This work contains a description of how the types of speech acts, which take place in the EFL class observed, are developed in pro of communication, and then constructed as a result of it. This research study then answers two questions: what types of speech acts emerge and are maintained in interactions between the teacher and the students in class? And, how do these types of speech acts potentially influence on both interactants’ interactional behavior in class? The analysis is done under the ethnomethodological conversation analysis approach in which the details of the interactions are highlighted to identify the speech acts with the development and potential influence they may have in the interactional behavior of the participants, the students and the teacher. The findings show that there are two main interactional patterns in the EFL class observed: asking about content and adding content. Both present characteristic developments and speech acts that potentially influence on the teacher’s and the students’ interactional behavior in this class. The findings of this research project will serve for reference and evidence of the patterns of communication that emerge in EFL classroom interaction and the influence they have on the way both interactants use the target language in classroom interaction.