My observation from using Duolingo (Spanish) was similar to this. My theory was that there spaced repetition was simply based topic and then once a topic was chosen it then decided what words to test you on. This is crude, simplistic and ineffective (IMHO). Like you say, there are words you see rarely.
Also, certain topics end up reinforcing earlier topics. I lost count of the number of times that the stupid "algorithm" would make me go through the exercise of translating "no, nada". At some point, don't I just know this?
Additionally, when you have topics that aren't "gold", it simply selects the first non-gold one to repeat. This can mean that a bunch of stuff at the bottom of the tree gets rusty because you don't get to it while you end up redoing stuff you know backwards.
I made this observation in the forums but couldn't really get any traction on the issue.
At some point they also introduced the stupid heart system, which was pretty much my trigger for just abandoning the whole thing.
Also, I'm really not sure how much this format actually works. Like having completed the Spanish tree, I'm honestly not sure if I really remember anything more than a small fraction of it.
Also, certain topics end up reinforcing earlier topics. I lost count of the number of times that the stupid "algorithm" would make me go through the exercise of translating "no, nada". At some point, don't I just know this?
Additionally, when you have topics that aren't "gold", it simply selects the first non-gold one to repeat. This can mean that a bunch of stuff at the bottom of the tree gets rusty because you don't get to it while you end up redoing stuff you know backwards.
I made this observation in the forums but couldn't really get any traction on the issue.
At some point they also introduced the stupid heart system, which was pretty much my trigger for just abandoning the whole thing.
Also, I'm really not sure how much this format actually works. Like having completed the Spanish tree, I'm honestly not sure if I really remember anything more than a small fraction of it.