Word memorability—the likelihood that a word will be retained in memory—is influenced by various psycholinguistic properties. This study investigates which psycholinguistic factors best predict a word’s memorability in both recall and recognition tasks. In addition to examining the well-established word frequency effect, we explore whether there is a potential letter frequency effect. We analysed word frequency, mean and total letter frequency, word length, number of vowels, and vowel proportion as predictors of memorability. Results from regression analyses confirmed a significant word frequency effect for both recall and recognition. However, no significant effects were found for letter frequency or other letter-based features. These findings reinforce the central role of word frequency in word memorability and suggest that additional, non-psycholinguistic factors may be necessary to fully account for variation in memory performance.