Language of instruction is a crucial aspect of teaching and learning process in every educational context. The language competence in fact can affect the degree of success of the students and their academic performance throughout their education; especially in postgraduate education level in a foreign language. In this case, it will be very difficult for the international students to pursue their education in an entirely different context with a language they learn for the first time. There is a sizeable amount of existing research carried out on the language difficulties of the international postgraduate students with the medium of instruction (mostly in English). The findings show that inadequacy in language utilization puts a profound negative impact on students' learning and understanding the intended content knowledge. Thus, the current study was conducted to explore the language difficulties that the international postgraduate students experience during their education at Turkish universities with the medium of Turkish, their applied strategies, the given supports, their suggestive solutions and expectations to reduce their current problems. The data was collected through a one-to-one semi-structured interview with 15 international postgraduate students from different countries pursuing their education in different faculties at Mersin University. The results of the study revealed that the main problem of these students was writing followed by speaking, listening and reading respectively. However, the problems related to the language skills were linked to other underlying factors such as poor vocabulary, fast speech rate of the instructors, structural aspects of the Turkish language and some others.