A common problem for tech-minded people when approaching human languages is to equate learning words with learning a language but it doesn't work that way.
The two big reasons are differing division of word boundaries and collocations. The second half of this 2 minute video explains both: http://www.youtube.com/watch?v=3cjnP6mogEU
Very true. One way around that is to put more than one word on your flashcard; a phrase of five-ish words enough to study in that way, but long enough to show some grammar and context ("the elephant has a long trunk").
The two big reasons are differing division of word boundaries and collocations. The second half of this 2 minute video explains both: http://www.youtube.com/watch?v=3cjnP6mogEU