Sixty-seven Japanese English as a Second Language undergraduate learners completed one smartphone video production per week for 12 weeks, based on a teacher-selected theme. Designed as a case study for this specific context, data from students' oral performances was analyzed on a weekly basis for their use of the Academic Word List (AWL). A post-intervention survey was also used to gather evidence pertaining to students' perception of the themes provided. The analysis compared the mean use of academic words against the various themes to determine their effect on AWL use. The findings indicate that there is a correlation between theme preference and the use of AWL lexical items. The research outcome indicates that the smartphone video recording feature can be used to encourage language learners to speak in the target language about relevant themes and thus increase speaking abilities and word usage.