Retention and learning are neurolinguistic and psycholinguistic processes. The brain electrical response to the cognitive processes that happen in the cortices is inescapable. During neuronal activities, created waves can be recorded and displayed by quantitative electroencephalogram (QEEG) in a non-invasive form. Beta waves are created by thinking, learning, computations, reasoning, attention, and problem-solving activities. This study's primary goal is to objectively investigate the variables impacts of multisensory and non-multisensory methods of instruction on vocabulary retention concerning beta and beta1 waves frequency changes. To meet the purpose, some pre-school novice male and female foreign language learners (age: 5-6 years) participated in this study voluntarily and were assigned into two experimental groups: The Multisensory (three girls and four boys) and Non-multisensory (one girl and six boys) teaching groups. The analyses of the collected data on pre- and post-brain QEEG records of beta and beta1/SMR waves' variations indicated no significant difference between the two groups in the brain oscillatory changes. However, the case study analyses specified the supremacy of beta1 frequency ranges in the Multisensory post-records. The comparative findings of pre- and post-Expressive One Word-Picture-Matching Test (EWPMT) showed that the Multisensory group outperformed the Non-multisensory one; besides, a significant positive relationship was found between beta wave frequency changes on Fp1 and mean score of EWPM post-test in the Multisensory group. The study concluded that the multisensory approach could be a promising method to improve retention at the pre-school level.