The purpose of this study was to investigate how the English speaking ability of Korean EFL college students was affected by their interactions with Talk-to-ChatGPT while taking an ‘English Interview’ class. Thirty pieces of English conversation scripts with thirty chatbot conversations created by five students were collected for analysis. Two online text analysis programs, Quillbot including word counter and grammar checker and T.E.R.A.(Text Ease and Readability Assessor), were used for data analysis. The findings of data analysis revealed that 1) The average length of the sentences and words spoken by the participants has increased through English speaking practice using Talk-to-ChatGPT, and 2) There was no significant change in text ease and readability, and coherence of students’ utterances through English speaking practice using a chatbot while there were differences depending on their English proficiency levels. 3) Students A, B, and D, who had relatively low levels of English proficiency, showed a slight increase in syntactic accuracy and semantic clarity in their English interview practice. Based on the study findings, pedagogical implications for the effective use of AI-based apps or programs in English speaking classes were presented.