Although the teaching of Turkish as a second language and as a foreignlanguage shows similarities in many areas, there is a major differencebetween them. The social contexts and cultural dimension of the languagecome to the fore if it is learned as a second language; because, the languageis learnt in that culture as a second language. Thus, the people who have asecond language are more advantageous than the other who learns the sameone as foreign language. In this study, it is aimed to identify and classifythe language usage of 10 foreign undergraduate students in ÇOMÜ. Thestudy was designed as a case study. Data of the study is obtained fromsemi-structured interviews conducted with advanced foreign students anddiaries that were kept for 30 days of their lives. In the study, 1165expressions were reflected into the diaries of advanced foreign students.According to the analyses conducted by three experts in the area, the mostdifficult expressions that give difficulties to the students are idioms (f=458), allusion (f = 288), metonymy (f = 166) and double-entendre (f=105).Apart from these, students have faced some figures of speech in the dailylife such as hyperbole, simile, metaphor, identification, kind assumption,proverbs, repetition, inquiry, interjection, symmetry, open metaphor,amphibology and riddles. This case has suggested that the literary languageshould be also used along with idioms, proverbs and expressions in theteaching of the second language. In the interviews conducted, it has beenindicated that the language of Turkish is rich in terms of the idioms and theadvance foreign students always face these idioms, they are frequentlysurprised by the sarcastic use of the language and sometimes ridiculed bythe misunderstandings and they also stated that Turkish has a highexpression of power.