Song lyrics are a series of words that form a song, consisting of several stanzas, refrains or choruses. Forming song lyrics is not as easy as compiling an essay, but it can be obtained in the form of one's expression such as experiences that have been experienced, things that have been seen or heard, and various inspirations. The writer will express his experience by doing word games and language so as to create interest and distinctiveness in the lyrics or verses. This research is qualitative research and uses qualitative descriptive methods, namely interpreting and describing data. The main object of his research was the song "By My Side" composed by David Choi and Dewi Dee Lestari. Using suposive sampling techniques, trianggulation of data and theory, descriptive analysis techniques and data collection, by reading and recording them.. Aims to know what languages are used and what message to convey. The result is that the code mix contained in the lyrics of the song is mix the code inward, which is Indonesian, and mix the code out, which is English.