How come sometimes the skill won't strengthen? Usually when I don't have full bars on a skill I can strengthen it and get back to full bars. However, a couple of times it stopped increasing the bars and won't go back to full. For one of them I did it 4 times before it went back to full, but for the other one I have already done it 5 times and I can't get it back up. How can I fix this?
I think it depends on the strength of all the words in the skill and how much they get strengthened by the exercise. The selection of the sentences and the words has a randomness which may not always choose the weakest words.