In Distributed Morphology, PF is the sequence of steps that a derivational chunk takes on its way to the externalization systems. This chapter argues that these steps are also integarated in the bilingual’s mind. The empirical evidence comes from clitic combinations in Catalan/Spanish and consonant mutation in English/Welsh. It is subsequently argued that even word order and prosodification are integrated. A section of the chapter is devoted to MacSwan and Colina’s (2014) ‘PF Interface Condition,’ which makes the prediction that one cannot code-switch within the word. I argue that code-switching does not obey this restriction andthe phonological effects that lead to this conclusion follow from phase theory.