Why won't Duolingo let me do strengthen skills?

When I try to strength skills, duolingo comes up with a message saying "you have practiced all your words, why don't you do some lessons or translations" (I assume it means immersion).

However, when I go to the words list, there are about 630 words which have only one bar of strength, and it says that they are overdue for practice.

How can I strengthen these words? Doing lessons does not help, as the words rarely come up in the questions. I don't want to do flashcards, as the wrong words come up, and then they decay back to 1 bar after just 24 hours. (For background information, I have completed my tree, and kept it gold).

August 14, 2015


Hi! I'm a Tester at Duolingo! Could you give me a little more information such as what language you are learning? And are you using a browser or the app?

August 14, 2015

Hi, I'm learning Italian (from English), and using the Chrome browser on my laptop.

August 15, 2015
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