In this trilingual study, our primary goal was to gain a better understanding of how second language (L2) readers' native language knowledge (L1) influences their L2 lexical inferencing from written texts and its outcomes. In particular, we wished to examine L1 transfer in L2 inferencing in terms of the relative typological distance between the L1 and the L2. What kinds of help – if any – may come from the readers' L1? What might be the importance in L1 transfer of typological proximity between the L1 and L2, reflecting similarities of linguistic features in the two languages? How might the relative typological proximity of readers' L1 to the L2 appear to relate to readers' relative lexical proficiency in the L2? To their success in L2 lexical inferencing? To their subsequent retention of new word knowledge?

To answer these questions, we carried out a study of the processes and outcomes of L1 lexical inferencing from written texts by speakers of three Indo-European languages (English, Persian and French) and L2 lexical inferencing by the latter two groups in English, using introspective methods – as reported in Chapters 3 to 5. In this research, readers were asked to try to infer meanings for specific text-embedded target words they didn't know, so that both the incidence of inferencing and their attention to many of these words was probably greater than would have occurred in a natural reading situation. However, the nature of the process and outcomes of our inferencing tasks correspond to those of reading situations in which readers are motivated to understand L2 reading texts and to attempt inferring the meanings of unfamiliar words they encounter while reading, as often happens with university students studying through a second language and with L1 readers of technical texts in an unfamiliar field.

We first sought to determine shared – presumably more universal – aspects of L1 and L2 lexical inferencing across the three groups.