In peer learning, students’ cognitive processes can manifest in verbal communication. This study investigated how students use spoken language to interlink their ideas in partner work (transactivity). In 83 university students, transactive statements were coded by raters via students’ content-related ideas and their link to their partner’s ideas. Analyses resulted in 27 lexical units, grouped into four clusters, that occurred more often in transactive statements than in nontransactive statements. In a cross-validation, students’ use of the lexical units correlated positively with their coded transactive statements and their learning results. We interpret the use of the lexical units as students’ attempt to establish logical relations between their ideas and their learning partner’s ideas, to signal tentativeness and insecurity about their ideas, and to invite the partner to elaborate on their ideas.