What a wonderful tool. Thank you.
A few suggestions.
1. It would be cool as an ESL student to have the word explanation in different languages.
2. Have a quick global option to cut out the main common words such as "and", "if", "but" etc ...
3. Keep the edit fuction (the pen/delete) to the far left and next to the vocabulary word because sometimes you want efficiency and you don't want to look far left and far right.
Customer support service by UserEcho