Codeswitching is a common phenomenon in popular music. The reasons for codeswitching between languages in pop songs are varied. To make pop songs more appealing to the listeners, codeswitching serves a range of functions, such as fitting into the rhyming scheme, marking text structure, indexing prior texts, injecting humor, and attention-getting. Apart from these functions, codeswitching is related to the broader socio-cultural context in which the songs are produced. In this paper, by investigating a corpus of Taiwanese pop song lyrics, it is found that some Taiwanese pop songs can reflect a huge influence of Japanese culture on everyday life of the Taiwanese. In addition, the paper also investigates how the so-called singer-writers with foreign- country-born backgrounds manipulate different types of music and switch between languages to convey their identities which may be genuine or purely market-driven.