Formulaic language, such as lexical phrases as hot as hell or pass the buck, in English is common in daily usage. Although formulaic language is common, the lexical phrases are often excluded from word lists. Second language learners of English need to use formulaic language to enhance their proficiency level. Beyond incorporating lexical phrases to word lists, other methods should be examined. This study examined the mnemonic benefit of noticing alliterative and assonant phrases with low and high proficiency learners of English. Previous research has shown that highlighting the concepts of alliteration and assonance is beneficial in recalling monosyllabic two-word units such as pet peeve or bite size. This study inquired whether the mnemonic effect is effective with longer lexical phrases beyond two-syllable phrases even when deliberative learning is not involved. Students from two public universities in Japan participated in the semester-long activity. The participants were asked to classify the phrases into different categories, and then recall the phrases over time. The results indicate that the mnemonic effect is not as clear with longer lexical phrases than it is with monosyllabic lexical phrases. Recall for alliterative expressions seemed to be better than for assonant expressions, but similar to non-salient expressions. Lower proficiency learners seem to process the longer lexical phrases similar to higher proficiency learners so the benefit of noticing alliterative and assonant expressions might be equal for both groups.