The relevant studies using a cross sectional view of speech organs supplemented with visuospatial cues and verbal text to explore EFL learners' learning effectiveness and behavior through mobile devices when learning English phonetics are scarce. This study was attempted to investigate whether the presence of visuospatial cues can benefit EFL learners with different levels of prior knowledge in learning English phonetics through mobile devices. The present study investigated the interaction between the experimental condition and the learners' prior knowledge on their task performances and cognitive load ratings. Fifty-six English as a foreign language (EFL) learners recruited from two sections of a linguistics course participated in the experiment. First, their background knowledge concerning English phonetics was evaluated to determine their prior knowledge level. Then, they were randomly assigned into two experimental conditions--picture-plus-text and picture-plus-text-plus-cueing. After the experimental treatment, the participants were administered retention and transfer tests as well as cognitive load measurement. Experimental treatment and prior knowledge were the independent variables, while retention test, transfer test, study time, and number of clicks were the dependent variables. The results of the present study emphasized the importance of visuospatial cues on inducing deep cognitive processing as indicated by the learners' test performance and study patterns.