Nigerian Pidgin (hereafter NP) has assumed elaborated roles and functions, gaining new grounds in different sociolinguistic domains as a result of its sustained social expansion process. One of the consequences of this increased dynamism of NP is the development of lexical items into grammatical markers which is an expected natural process. In this paper, we examine language-internal mechanisms that transform lexical items into morphosyntactic items either for semantic value, creativity, expressivity or routinization. Our basic argument is that grammaticalization in NP is not contact-induced but a language-internal phenomenon, which reveals that NP has both a synchronic and diachronic existence that are imperative in evolving its unique grammar.