Second language acquisition researchers (Dulay and Burt 1973, 1974a; Bailey, Madden and Krashen 1974) have claimed there exists an acquisition order of English morphemes to which ESL learners, despite their different ages and language backgrounds, adhere. Thus far, however,anexplanation for the occurrence of such a morpheme order has eluded researchers.A study by this author was designed to yield data which would hopefully suggest a reason for the reported morpheme sequence. After analyzing the data in light of possible explanations, a significant correlation was found between the common morpheme difficulty order of the learners and the frequency of occurrence of these morphemes in adult native‐speaker speec