This chapter accesses the degree of national and international intelligibility as well as methods of creation of grammatical and culture-related innovations which reflect the Nigerian flavor in Nigerian English usage. Data were obtained through questionnaires, journals, books, and the internet. The Generative Lexicon Theory was used as the theoretical framework to address issues of compositionality and creative use of words as denoted on the basic lexical categories of the language. The aim was to define the boundary between variants and errors in grammatical and culture-related innovations in Nigerian English usage. These variant forms are expressed through grammatical shifts, borrowing, compounding, proverbs, and code-switching. The chapter provides answers to questions of acceptability and the common core features of these innovations. It concludes that these created words reflect Nigerian cultural norms which qualify them as variants of metropolitan forms of the English language and recommends that curriculum planners structure language courses to include Nigerian English usages.