The primary goal of language teaching is to afford learners, proficiency in communicating in the target language, self-development as well as intercultural understanding of languages in the learning process. The teacher is therefore charged with the task of selecting appropriate strategies to effectively achieve his pedagogic goals, one of which is the use of Code switching and Code mixing. Traditionally, this strategy has been viewed negatively as signs of deficiencies in a speaker, though in a typical multilingual setting, speakers tend to select multiple codes or mix languages they consider appropriate to facilitate and clarify meanings in their language expressions. This study intends to project the socio-linguistic functions inherent in code switching and mixing that can help ESL students transcend from the known (L1) to the unknown (L2), especially in learning complex language contents; making the teacher's work, productive and less strenuous. A quantitative methodology was adopted to ascertain the efficacy of code switching and mixing as a teaching strategy. The results revealed that Code switching and mixing have progressive and positive effects in language learning, both for the teacher and learners in the ESL situation.