1. Forum
  2. >
  3. Topic: Duolingo
  4. >
  5. Why does 'Practice Weak Skill…


Why does 'Practice Weak Skills' often not refresh any weak skills?

Since the new update on IOS, I've been experiencing issues with the 'Practice Weak Skills' lessons and their ability to refresh decayed lessons.

Only sometimes does this actually work to refresh weak skills, and quite often I will complete several lessons of 'practicing weak skills' and find that it has not made a single one of my lessons go gold (even if I know that material covered in my practice was contained in one of my decayed lessons)

Has anyone else experienced this? It seems only logical that this feature should refresh skills more frequently than once in every 4-5 practices (the average rate that I have been experiencing)

August 6, 2014



As a course contributor, I have to agree with Doug's assessment. In regards to the Spanish for English speakers course, I can confirm that these practice activities do in fact exist within the course and have not been altered, so it could be that the algorithm that winds the crank of duolingo practice sessions is "scrambling" the exercises but some are getting stuck to the side of the bowl, so to speak- not getting mixed in like they should be. I'm in the process of consulting with other contributors in order to figure out why this is happening, but for now this is my best guess. ¡Seguimos adelante!


I'm still experiencing a similar issue which may be related. on my weak words list - the weakest word is "Caminas"- I've been doing "practice" sessions in the skill lesson that this belongs to, 2 or 3 times per day for the last 2 weeks, and through this all, Duolingo has not given me the word "Caminas"to practice.

I'm not sure how to get Duolingo to focus on the weakest words - Moderators, is there something I'm doing wrong?

Please feel free to use my data as a reproducible example.


My problem is that my weak words aren't actually strengthening after the practice session. I took a word count and i have 369 words with one bar of strength. After three practice sessions is was still left with 369 words with only one bar of strength. Sometimes i will revise a word several times in a session and then when i look in the word list it still has only one bar of strength. Its really discouraging when you cant see the progress being made


I've had that too, when a word that just appeared in my practice session is still listed as "1/4, last seen 1 year ago". I reported it as a bug.


I'm experiencing the same issue.


I've experienced the exact same as you. And now, the skills' names are only ! for me. :/ This update was not the best...I hope we see a true bug fix (and restoring of old features) soon.


I have the same issue in Spanish. For me it seems that certain lessons cannot be refreshed fully. For example, just now I was able to refresh Idioms, but not Verbs Past or Verbs Present 3 in spite of passing the refresh lessons


Just to update this thread too: I am able to update to gold if I pass the refresher enough, so I understand the mechanism better, thanks to pinkodoug and Usagiboy7 on the other thread. User expectations still should have been handled better, especially as this apparently did change former behavior (I came on after that). The word "implicit" was used by pinkodoug and as a software designer, if that word was mentioned in a scrum or meeting, there should have been an immediate intervention by the other duoLingo devs. One can never underestimate the intelligence of one's user community; I am a prime example. :)


Just to be clear, the changes in January didn't really change the former behavior, it only changed the way that it was described. I think it was much clearer before, and the changes obfuscated things a bit. As I said in another post, I agree that some of their descriptions are lacking, and could be improved. It would be better, imo, if these sorts of things weren't merely implied, but explicitly stated.


There are a couple of things at work here.

To start, the strength of any given skill is based in part on the average strength of all of the word forms taught within that skill. A given skill might have anywhere from a dozen or so words to over seventy. Any time you use the strengthen skills exercises, whether on Android, iOS or the website, a maximum of 9 words are targeted for improvement by the app. These are typically the 9 words with the lowest strength rating, but there are some exceptions and some bugs that can affect this. If you complete a practice with no errors, those nine words will be raised to full strength along with a varying number of other words, depending on which sentences are presented and how they're configured within the course.

Because your nine weakest words at any given time probably come from a number of different skills, we can see why it can take several global practice sessions to see any one skill improve. For this reason, the surest and fastest way to get any skill to strengthen is to do practices specific to that skill, but even then it might take several practices to raise the average score of the skill's constituent words enough to bring the skill back to a golden state.



If it is the case that passing a refresher lesson may not bump up the status, then Duolingo needs to make that clearer to the users. Immediately they can post that on the site somewhere and then in an update, include a third status for refresher lessons: "Passed but not enough to bump." They need to manage user expectations.


I agree that some of their descriptions could be better, but I'm not sure that it's a reasonable expectation that one practice session would bump the status of an entire skill containing 70+ words. Plus, there's an implicit notification that you passed but didn't do enough to bump the skill when you successfully complete a practice and it doesn't bump your skill.

Some of this disconnect between the way a practice works and the way it's described is an artifact from the UI redesign at the beginning of the year. Prior to the revamp, descriptions were more "words based" rather than "skills based". The devs made a decision to describe things at the skill level even though much of the underlying functionality operates at the word level. Skill strength indicators were added, which as I said are merely the average of the skill's individual word strengths. With the old system, a user was presented with a list of words that were strengthened at the end of any practice session. This made it very clear what exactly you accomplished with your practice, plus everyone had the vocabulary list and could immediately see what words were strengthened. Things are a lot more vague now.


Thank you for the thorough explanation pinkodoug, you provided a lot of insight into the inner workings of Duo that I hadn't considered before.


Oh, a "here is what you learned" list at the end of a strengthening session would be super helpful for me, especially if words that I was struggling with in the lesson were identified.

  • 1333

I've been experiencing this as well, even at this later date. My problem was that even trying to "strengthen" the individual skills (conjunctions, for example) would never increase that particular skill level to gold. Since I like to have everything at full strength, this was pretty annoying, especially after practicing over and over and over again.

For anyone else experiencing this, I think I found a work-around, in that practicing the individual lessons within a skill rather than using the "strengthen skills" button can by itself raise the level to gold. I got this to work for two different skills that wouldn't increase to gold using the strengthen button. Granted, I only tried this by redoing the lessons with the words I was seeing in the strengthen exercise, so I'm not sure if it will work by practicing any random lesson within a given skill.


Yes! Thanks for this tip, I also like everything to be gold and after refreshing an excercise about 7 times was able to get it to full strength using this method. Thanks!


Hi there Duolingo team,

I'm not sure if you read these forums, however after many weeks of practice it seems that several words in the Spanish course do not have exercises available to refresh / strengthen them.

I'm making this assumption due to the fact that I've been refreshing / strengthening weak words on Verbs Present 1 for weeks now (because they are appearing with a WEAK rating under Words), but still these words remain stubbornly absent from practice sessions.

Examples being: - Caminas - Cocina - Tocamos - Cocinan - Hacemos - Haces

I would be very happy to help with closing these gaps by creating some targeted practice sentences - just need access and guidance to do so. Alternatively - I would be happy to work with your team to identify the cause of the issue, and hopefully creative ways to auto-find sentences that can fill these gaps by using targeted internet searches (in other words - if you search for any sentances using the word "caminas", which only uses words that were within the vocabulary by the time the student got to this lesson, it should be possible to quickly create a diverse range of relevant practice sentences with very little effort)

Many thanks Sean


Hi there Duolingo Dev Team

Any luck in finding the underlying cause of this issue? Many users (myself included) are experiencing an issue where the strengthen or practice functions are not targeting the weakest words - but instead we're getting other sentances coming up frequently which only use stronger or strong words.

I would hope that the algo could be changed to be more similar to Anki where the weaker words bubble up to the top of the review stack first (so you target weakest first).

If I can be of help in providing examples or demonstrating the issue, please let me know Sean


Hi sean.b.adams,

Thanks for reporting this with detailed information. It seems your word strength is currently low for the word haces, and doing a global practice lets you review that word.

We recently added a capability to make weak words more likely to show up in skill/global practice sessions. We are aware there are some remaining problems in practice, which will be fixed in the future.


Thank you - appreciate your help on this - I will give this a try. Have a great Wed Sean


Hi hideki, I've been working through this for the last few weeks, and "haces" and "quieres" are still on the list as weak words (in fact "haces" has not come up for practice in 6 months despite frequently using the practice for "verbs present 1", and "quieres" in 3 months)

Interestingly though - many other words come up all the time, even though they are already strong, like "bebo" or "lee".

looking forward to any further tweaks you can do here to force the weak words to have highest priority!

Thanks Hideki


I am having the same issue as Sean. Global practice and strengthening skills never provide an example with these words even after extensive repetition. I am seeing the issue with many of the same words that Sean mentions. Notably Haces which I tried to target for a while to see if I was just being unlucky with the presented exercises, another example is abuelo.

Learn a language in just 5 minutes a day. For free.