The effects of oral incidental focus on form on developing vocabulary knowledge

Previous studies on lexical focus on form (FonF) have mostly centred on FonF in reading with a few pre-selected lexical items. This study investigated the contribution of oral incidental FonF to developing learners’ lexical knowledge in a free discussion EFL class. Incidental FonF was provided to 15 upper-intermediate learners who participated in 10 sessions of a meaning-oriented class. To gauge the retention rate of the lexical focus on form episodes (FFEs), two individualized multiple-choice achievement tests based on the lexical FFEs the learners reported to have no previous knowledge of in their uptake sheets were administered every five sessions, and two delayed posttests were given five weeks following each immediate posttest. Moreover, the participants were asked to compose two prompt-based writings on topics selected out of the covered themes in the posttests. Thematically relevant lexical FFEs extracted from each learner’s uptake sheets made up the tailored prompts per learner. Results indicated rather high effectiveness of oral incidental FonF in developing learners’ receptive and productive lexical knowledge in both short and long terms. The findings also revealed that learners fail to develop knowledge of the grammatical aspects of some lexical FFEs if their attention is merely drawn to their meaning aspects.