This paper examines the possible interface between contact linguistics and second language acquisition research by comparing the institutionalized second-language varieties of English known as “New Englishes” and the foreign varieties of English called “Learner Englishes”. On the basis of corpus data representing several populations of various origins, it investigates four linguistic phenomena, ranging from syntax (embedded inversion) to lexis (phrasal verbs with up), through phraseology (word clusters) and pragmatics (discourse markers), with a view to identifying similarities and differences between the two types of varieties at several levels of the language. The paper also explores avenues for going beyond a descriptive account towards a more explanatory one, in an attempt to build the foundations of a theoretical rapprochement between contact linguistics and second language acquisition research.