The present research falls within the domain of variational linguistics, it is focused on the study of the variability of the language used by the inhabitants of the Upper Valley of the Mureș and is a sociolinguistic approach from a synchronic and diachronic perspective. In a previous linguistic study (Rus 2012, 219) it has been noted that within the subdialect spoken in the Upper Valley of the Mureș, the influences of the Moldavian subdialect, as well as those of Hungarian can be traced. However, the influence of the standard language among young people, but also among the people who have a higher social status, is obvious. In the determination of the physiognomy of the dialect, one must take into account not only its formation mechanisms but also the transformations occurring as a result of the influence of the standard language or the contact with other languages. Therefore, I will consider the degree to which the dynamics of the subdialect are influenced by the standard language or by neologisms, but also the determination of the dialectal linguistic competence and performance according to sociolinguistic criteria (gender, age, and social status). In the Upper Valley of the Mures, there are common and distinctive features of the use of language between members of different ages, statuses, and genders. However, older people tend to use more frequently the specific particularities of the subdialect, whereas the younger ones or those who have a higher social status use constantly literary language or even neologism, even though they know the subdialect.