You might also want to try one of the other vocabulary trainers I have found (sorted by the time when I found them):
QVocab (Qt™)
Vokabel-Trainer (Tcl/Tk)
Lingvisto (X)
KVoclearn (KDE)
SVT (console)
chflashcard (X11, for Chinese)
Vocabul ary Trainer (freeware, all flavours of Windows®)
The author of this application has also written a theoretical article about learning languages (German only).
wordtrain (console)
vocabbox (Python Qt™/KDE)
DokVok (KDE)
Wordlearn (Windows® 32/commercial)
GVoctra (DOS)
Vocitrainer (Mac/Win32, commercial)