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[Bug] SRS and/or new Words list "Strength" not working correctly

For today's practice, I opted to do something I haven't been able to do for far too long: use my Words list to Practice Weakest. However, the session I was given was not at all what I expected.

I was asked about "having", and "drinking", "water" and "coffee". These are early and basic concepts that anyone beyond beginner knows well. In my words list, they all have 4 bars/full strength. On the other hand, words that I haven't seen (according to the list) for 7, 8, and even 10 months did not appear in the session at all. Words that I know I do not need are given, and words that I can barely remember exist are skipped.

(Note: I realize that you have to complete sessions to get new content, but this is not my first "Weakest" practice session since yesterday's return of Words -- it's my third or fourth.)

I was seeing much the same behavior before the Vocab page was removed, so I'm guessing that the backend -- which was apparently broken in this way before -- still suffers from the same problems. In fact, this is one of the first assumed bugs I reported to Duo when I first joined.

Please look into this; it's likely there are fairly significant bugs lurking.

June 13, 2014



This is almost definitely broken. Today, when I did my Practice Weakest Words session, I took down the exact count and list of single strength, weakest words in my list. I practiced and completed the session. After, the list was still exactly the same.

It is broken.

Edit: grumpypants!


Another day, another Weakest Words session, and another unchanged list. I still have the exact same words at one bar strength despite almost a week of practicing "them" (whatever DL believe is them).

Anyone from staff has a response to this? Is this a known or acknowledged bug?


I have the same problem! I have done bunches and bunches of strengthening / practicing. I have recorded my list of weak words and even when I get one of my weak words and answer correctly, the strength and date practiced (for that word) does NOT update...even when that word is practiced multiple times. I have tried choosing to strengthen individual skill sets to reduce my weak words...and force Duo to give me certain words to practice. It has helped marginally, but still there are quite a few words that just won't update!!! Sigh.


For the record (@the mod who suggested this topic be moved), part of why I didn't put this topic in troubleshooting from the start is because it will get much less notice. This forum gets far fewer reads and readers than main discussion, so very few will see it to comment/agree/disagree give feedback.


I understand that, it's normal since people will only go into troubleshooting if they have a problem. But unfortunately if everyone put their thread in the Duolingo section simply because they get more visibility, no one would ever use "troubleshooting". We have to keep the threads as organized as we can, that way, only people who are here to help and the staff will focus on your thread, and it won't be lost in the mass.

If you need, you can use the "Support" tab on the left side of this page, it'll send your request to the staff directly.


Or you could just keep practicing until Duolingo tells you that all words are strong!


I think the logic behind all this must be much more complicated than just assembling some sentences which include my weakest words. That's because the concept of a "word strength" is quite limited by definition. It can only give information about that particular word, about my ability to understand and translate it and maybe to produce a certain conjugation or declension. And the strength of an individual word form, as we can see it in the vocab, is even more limited in it's value.

But the task for the user here is translating a sentence, and this involves much more than knowing an individual word, it's about knowing how to use words together in the right way to express a certain meaning. So I would expect that there is also the concept of a "base word strength" involved (in contrast to the individual word form we are speaking of here) as well as a "sentence strength". I'd also expect that they measure the answer time, even in non timed practice, and that sentences with long answer times are taken as a vote for more occurences of that sentence (or similar ones). Maybe there is even totally sophisticated machinery involved like a neural network that is trained with the practice sentences and my responses and tries to predict the sentences I might have difficulties with. Who knows? All this could lead to the confusing observation that there are word forms with low strength, but the engine gives me totally different sentences.

But until they provide more information about how all this works, it will remain speculation, but we also cannot say for sure that it doesn't work. However, I doubt that there will be much more information, as they probably want to scientifically publish their findings and algorithms.

All in all, I think it's necessary to give the users the option to choose themselves the words and sentences they want to practice, so when they think that the engine doesn't give them the right stuff, they just can do it themselves. After all, we are grown up people and should have the possibility to choose our own direction.

Edit: Did you explicitly check for weakest words, or for words you haven't seen in a long time? I just tried it out, and I must admit the "practice weakest words" did what the name says - it gave me the 8 words with the lowest strength as shown in the word list. Next, I did a "strengthen skills" from the main page, and it was the same, again the 7 or 8 weakest words.


Yep, I went in and checked the list. There are more than 3 pages / ~50+ words that have a strength of 1 bar/weakest. I was not tested on those. And the words that they did test me on -- coffee, bread, water, and the like -- are all 4 bars/full strength.

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