This study investigates the morpho-syntactic properties of the English to- infinitive, progressive auxiliary BE, perfective auxiliary HAVE, passive BE and HAVE, and their Nàijá translation equivalent. (Nàijá is an English-lexifier Nigerian creole.) The adopted theoretical framework is the minimalist program (MP) of generative syntax. The objectives of the study are (i) to determine the errors which Nàijá L1 learners of English make in learning these delineated aspects of English morpho-syntax, and (ii) to explain why they make these errors. The data analysis shows that Nàijá L1 learners of English generally (i) substitute the Nàijá verb phrase structure for the English to- infinitive structure, (ii) shift temporal marking in progressive tenses to a temporal adverb, bifọ (somewhat equivalent to English ‘before’), (iii) impose the morphologically invariant structure of the Nàijá perfective auxiliary dọn on the English perfective auxiliary HAVE, and (iv) in passive structures, equate the English 3rd person pronominal they with the Nàijá passive nominal marker (pnm), dẹm.