In the study conducted using qualitative research methods, one of the purposeful samplings, typical case sampling was used. The date were collected from two sources. The students were asked to prepare any topic they wanted and then delivered it. The students were observed for one month in order to detect their mistakes as they speak, through participant observation. Expression mistakes were classified and interpreted before they made them. Mistakes in one sentence considered for more than one category were classified under all categories. In addition, both in data collection and analysis, validity and reliability measures were taken. At the end of the research, we found that Turkic students made errors more in sentence components followed by compounds errors, errors originating from the use of plural morpheme, temporal-personal morphemes. We also observed that Turkic students made minimum errors in voice, conjunctions-prepositions and verbs.