This paper entitled “Language Use and Social Network: An Emergent Variety” examines the use of language in social network sites. The paper adopts the Systemic Functional Grammar SFG) as its theoretical framework. This framework is an approach to sociolinguistic study. A central theoretical principle is that any act of communication involves choices. Languages used in the social network sites are a system of choice and a variety. However, this theory has been useful as it helps the researcher look into the choice of language by students over the social network sites. Data were elicited through the instrument called “Language and Social Network Questionnaire” and analysis done using percentage and frequency counts. The results of findings reveal that presently languages used by students over the social network have shifted from the act of fine writing, correct spelling and pronunciation to the use of graphemes. Students’ respond to this is evident in the uncontrollable use of undecipherable initials, abbreviations, numerical slangs among others to effect communication. Findings also reveal that this usage is appealing to students and the resulting effects are noticeable mostly in students’ academic work. Interestingly, it is also revealed that these lexemes/graphemes reveal a phonological process called ‘deletion’ in particular as well as some phonetic and syntactic features. In view of this therefore, it opined that seeing to the excessive use of these undecipherable initials, abbreviations, numerical slangs among others, their continuous use should be minimized and context of usage should as well be taken into consideration.