This article is intended for both the teachers involved in the professional training of pre-service teachers, as well as the pre-service teachers. The professionalism of the teacher is determined by several factors. An essential factor in this context is the competence of public speaking. The efficiency of public speaking is determined by the quality of the three dimensions: ethos, pathos, logos. This article reflects epistemological landmarks in the development of logos. The Logos appeals to the rational part of the public mind and provides support for assimilating the essence of the subject expounded by argument. Therefore, the development of the Logos is a continuous process that involves the elaboration of oratorical speeches based on arguments. In this context, the purpose of the research is testing the students’ level of logos on the development of the skills to build arguments in oratory speeches based on a logical structure. The sample consisted of 50 pre-service teachers from the Faculty of Psychology, Educational Sciences, Sociology, and Social Work at Moldova State University. The students filled a questionnaire consisting of 10 items that cover some basic aspects of logos. The data reveals that the respondents are partially aware of the structure of a public speech. At the same time, students are convinced of the necessity to use arguments in discourse but are unaware of or incorrectly identify the elements of argumentation in a text. Thus, we infer the necessity to develop argument-building skills in public speaking based on a logical argumentative structure for students.