My interest in the role a learner's linguistic environment plays in the process of acquiring a foreign language came out of a decade of teaching English to adult speakers of an array of other languages, in particular those whose jobs often required them to perform extraordinary feats in the English language with minimal training. I prepared them as best I could for their respective presentations and meetings, sharing the responsibility for what would result in either success or failure. The stakes were often high. Beginning to wonder to what extent my interventions helped, I made an attempt at determining the types of interventions that seemed at once most beneficial and economical. Although I found some ephemeral solutions, I was far from satisfied. I sought to learn more about what my students actually got from what I provided. Little did I know at the time that this was the beginning of a long journey into the study of initial processing of foreign language input.

Having expressed my interest in examining how learners work on second language (L2) input, I was given the responsibility of a pilot study at the University of Paris VIII on French learners of Polish at the absolute beginning of the acquisition process (cf. Rast, 1998). Following the pilot study, with the help of many, I conducted a large-scale observational study on initial processing of L2 input in adult second language acquisition, the material from which provides the foundation of this book. My initial questions included the following: what knowledge does a learner bring to the acquisition process? How, when and under what conditions do learners rely on target language (TL) input, on their native language (NL) or on other known languages to acquire elements of the TL? What strategies do learners use to accomplish a task in the TL at the moment of first exposure to that language?