The aim of the present study is to describe the relationship between linguistic and social factors in examining the language shift of Urum, an Anatolian Variety of Turkish spoken by Greeks from Georgia who currently reside in Greece. The ancestors of the Urum speakers came to Georgia from cities in Northeastern Anatolia (Kars, Erzurum) in the beginning of the 19th century and since then continued using the varieties of Anatolian Turkish in contact with the languages of the new environment, especially Russian, Georgian, and Armenian. When the Soviet Union collapsed in 1991, significant migrations of Greeks from the former Soviet territories took place, with the main destination being Greece. In this paper, evidence will be presented to show how the significant social transformation of the Urum-speaking community after the migration to Greece (external factors) has led to changes in its ethnic self-perception, since the ethnolinguistic identity of Urum speakers is no longer used as an important distinguishing feature. In addition, this study will investigate different levels of individual’s language competence, in an effort to understand additional factors that contribute to language shift. Broadly speaking, we will focus on Urum speakers who did not acquire a certain level of proficiency in the language, and they are unable to use it in socially significant ways, while, in our view, it will be a real challenge to pass that language on to children. Thus, the co-examination of the interaction between language-ethnic identity as well as of the pivotal role of other sociological factors that affect speaker’s linguistic behavior and language competence as such, can shed light on the process of language shift and its structural consequences. Therefore, attention has been focused on certain processes of linguistic change that occur during the contact situations between Urum and Greek observed mainly in phonology, morphology, syntax and lexicon and which may stand as indicators of language decay and language loss. In order to collect the linguistic data we used quantitative as well as qualitative research methods with different speakers of the community, from the fluent to the so-called semi-speakers so as to determine the impact of several external factors on speaker’s behavior that lead to structural consequences and subsequently affect language maintenance itself.