This document discusses two types of code-switching used in Asian pop music to create authenticity: phonological and lexical. It provides an example of each from different songs, explaining how phonemic ambiguity is used in one song to code-switch between English and Japanese words, while another song inserts Malay words into an otherwise English song to express emotions and situations. The document lists several references on the topics of language variation, authenticity, and code-switching in popular music genres.