Would it be possible to do something about the 'practicing all' mode? I'm practicing a lot but it seems that I get only the last learned sentences and words most of the time. When I look in my vocabulary list there are a lot of words I haven't used for a week, although I practised a lot. It would seem logic for me to practice all words when I choose ' practice all' and not only the last learned senteces.
Are more people having this problem?
Duolingo has a way of estimating "word strength"; your memory of a word based on the times that you have practised it and the time that has passed since your last encounter with the word. The reason why Duolingo calculates that is because words are taught through "spaced repetition". This means that you will repeatedly see the same words to help you remember them but the time between these repetitions increases constantly as you will start to remember words longer. The "practice all" mode provides you with some of your weakest words and these weakest words can indeed be words you've just learned as you haven't had much practice with them yet. Once you have practised new words a couple of times, they become more common and they start mixing with older words that are scheduled for practice.
You are not the first one who is confused about this and who expects a purely random set of words. Duo2012 suggested that there could be two buttons: one for random and one for weakest words: http://duolingo.com/#/comment/304475 That might solve the confusion, but I would like to point out that you are more likely to see recent words in your practice if you spend a lot of time on new lessons compared to practising previous material. People might therefore still have the same problem with the practice mode unless they practice regularly.
The weakest words button is in the full vocab page for each skill.
An example from French : Basics 2
The "practice weakest words" button is part of Vocabulary. If you click it then you will practice what you have selected in Vocabulary. This could be everything in your vocabulary, a skill or a lesson. That's why it isn't called "practice a skill"; you could be practising something else. If you hover over the "practice skill" button then you can read that you use it to strengthen the words in that skill. I think that you give too much weight to the words on these buttons. "Practice your weakest words" means "Practice your weakest words from what you have selected within Vocabulary" and "Practice skill" means "Practice your weakest words in this skill".
Thanks for the replys. I still don't understand it at a whole I guess... I already practice quite a lot and there are several words and grammar that I only got in a specific lesson and not in practice. (Words like towel' and daquela in Portugese). I understand that I can practice this in the specific lesson, but the thing is that I would like to practice it random, so I dont expect the words coming up and I dont always know in wich lesson I can find the words. But anyway, I understand that I have to practice even harder to get new words in practice:-)
Besides of this I love DuoLingo and for me it works better than Rosetta Stone.