Codes refer to the different language varieties or dialects used for meaningful communication.Code-switching and mixing behaviours that refer to blending of two or more languages or codesare common among bilingual and multilingual individuals. Communication practices in recenttimes have changed significantly due to the diversified technological advancements. Socialmedia have made communication around the world quick and convenient. The youth whoacquire various foreign languages and engage in social interactions become accustomed to code-switching and code-mixing behaviour. The research reported in this paper followed a qualitativeapproach to identify any possible influence of social media on code-switching and code-mixingbehaviour among the Bangladeshi youth. It examined if the mother tongue is endangered due tothe over-switching and over-mixing of codes in regular communication. The findings indicatethat social media served to mould their language varieties and influenced them to switch and mixtheir language codes. Moreover, it was evident from the findings that the switching and mixingof codes have significant consequences for the vitality of their mother tongue. The findings haveimplications for multilingual practices involving social media and language use among theyouth.