Abstract
This study investigated the difficulty rankings of English prefixes among Japanese adult learners of English (JLEs) and proposed six graded prefix difficulty rankings for facilitating teaching of vocabulary. The idea of the rankings was originally proposed by Bauer and Nation (B&N) (1993). They worked out a set of seven prefix ‘levels’ based on the criteria of frequency, regularity, productivity, and predictability of the affixes (prefixes and suffixes) for all English language learners. However, since B&N’s (1993) levels have not been demonstratively examined, it is not clear if their difficulty levels are valid. Therefore, this study attempted to find out whether B&N’s (1993) levels of prefixes suitably reflected the prefix difficulty rankings of JLEs. A test designed to assess knowledge of 22 English prefixes was given to 135 JLEs. The results showed that the findings partially overlapped with B&N’s (1993) difficulty rankings, but had some crucial discrepancies as well. The authors thus propose alternative rankings for JLEs based on the results. They also discuss possible factors affecting the rankings, and tentatively conclude that the effect of loanwords from the English language would be a primary factor, as indicated in Daulton (2008, 2009) and Mochizuki and Aizawa (2000).