vocabulary seems to relate to speaking ability substantially and to be probably the strongest of many speaking ability components (e.g., pronunciation and fluency) at the beginner level, although each study has its own weakness. It is also interesting to review the studies above with special focus on the aspects of vocabulary they targeted. The four studies (Adams, 1980; Higgs & Clifford, 1982; Koizumi & Kurizaki, 2002; Takiguchi, 2003) dealt with a relationship between (a) speaking ability and (b) vocabulary used in speaking performance (vocabulary performance), and the degree of associations were rather strong. On the other hand, Ishizuka (2000) examined an association between (a) speaking ability and (c) vocabulary stored as knowledge (vocabulary knowledge), showing a moderate relationship. Therefore, the results above can lead to the following hypothesis: The relationship between speaking ability and vocabulary performance is stronger than the one between speaking ability and vocabulary knowledge