In a multilingual setting like Nigeria, for inter-ethnic trade and commerce to be successful, trade and commerce has to be conducted in a language that is not only understood across ethnic boundaries, but also in a language that spans across both the intelligibility and identity of the interlocutors in order to win over, maintain customers and ensure better service delivery. This paper provides statistical data of such motivation for language choice in the banking sector. Although English is the transactional language in Nigeria since it is the language used with the purpose of getting things done in a formal setting. The research goes a step further by attempting a repositioning of indigenous languages in the country’s trade and commerce for efficient and effective interactional and transactional purposes. Using the Markedness model by Myers-Scotton, and the Communication Accommodation Theory by Giles as theoretical framework, this study attempts an assessment of the functionality of CS in a market situation with emphasis on the banking sector. It seeks to interpret the conversational motivations of CS, the immediate functions that it carries out and at the same time its organizational role in the progress of bargaining interaction as a whole. Using a questionnaire administered at four banks to 100 bankers and theircustomers, the research findings revealed both parties accommodate the other’s language which results in a switch to make unmarked, marked, explanatory choice as well as CS itself serving as a marked choice.Native language use is also found to be powerful negotiation tool functioning as a ‘transactional code’ or ‘we code’ during a bargaining procedure with both the bankers and the customers making choices within conversations to achieve desired conversational and functional aims.