I've noticed that from time to time, the words we have learned will change slightly. This is presumably in response to feedback from users, and I think it's great that you're listening and making these changes. However, I think some more thought needs to go into what happens when changes have been made. To explain, let me use an example from the Introductory French course. One of the translations you learn in the course is 'next to'. I learned this some time ago as 'à côté'. Today, I was tested on this, and entered 'à côté' as my answer, but discovered that it was only 'nearly right'. This was because the translation had been changed to 'à côté de'. I understand that this new translation is more accurate, and like I said, I support these changes, but it's very confusing to find out about them this way. I think if changes are made to words that a user has already learned, they really need to be notified of the change, and given the opportunity to relearn the word if they wish.