Despite the significant impact of the lexical approach for vocabulary learning, its classroom implementation has not been uniform. While related activities share the common Observe-Hypothesize-Experiment (OHE) elements, practitioners and researchers do not highlight how language input from the observing stage is turned into output and at what stage of learning it is likely to be most challenging for learners. The article reports on one classroom action research conducted on two groups of non-English-speaking university students. This present study investigates whether language proficiency plays a role and which stage of the OHE learning process deserves special attention. Different types of learning behaviors were found, and pedagogical implications that contribute to implementation of the approach are discussed. The paper argues that the OHE paradigm is not complete without immediate feedback, a component that has historically been impractical in formal EFL contexts and that AI-driven feedback should fill in the gap by enhancing the effectiveness of the lexical approach.