General beta feedback regarding difficulty
I see that this course is still in beta, so I just want to give a bit of general feedback (intended as constructive criticism, not just plain criticism):
For me, at least, this is much, much more difficult than any other Duolingo course I've tried.
I imagine that at least some of that is because Klingon was designed to be "alien". But I don't think it's all because of that: I'm OK at French (and was so before Duolingo), so it makes sense that would be easy for me, and Duolingo Spanish has been mostly easy probably due to similarities with French and also due to general exposure that you can't help but get a bit of in the US. But I'm also trying Russian, which is in a lot of ways totally foreign to anything else I know. Duolingo Russian is much easier than Duolingo Klingon.
It really seems to me that there's just so much jammed into a small number of lessons (relative to the other Duolingo courses). I'm constantly wondering, about lots of different things, "When did I supposedly learn that?!". But regardless of whether it's true that there's more stuff jammed in here, or if it's just that it's more difficult due to the "alien" design, perhaps you should at least consider slowing things down, spacing lessons out, and giving a lot more repetition for basic concepts.
I actually found the Klingon course, which I started when it first came out with no prior exposure to the language, very well paced compared with some other Duolingo courses. Reading the Tips & Notes is essential, though.
If you want an example of a course that really does too much, too fast, try Hungarian. :-)
The tree was very well paced for me. You will never be able to make a single tree that accommodates everybody because people vary so much in their learning speed and capacity. You will also get the most questions and complaints from the people having difficulty so that might skew you to believe they form the majority. Per percentage of the population, they do actually but are they the majority of people who will stick with Klingon?
The optimum would be to have at least two different trees with different pacing and levels of abstract reasoning required. But as I think you have to confine yourself to one tree, perhaps instead you could have more example sentences in the lessons with level one questions being easier and later crown levels more challenging. This is why in Japan, schools place their students into different classrooms and different high schools based on academic proficiency and why America used to have honors or gifted and talented programs standard before the days when everybody had to get a trophy. It just is not possible to have a one size fits all model that will meet the needs of all learners. Duolingo is a great start for computer learning of language but it is still very rudimentary because it is not adaptive. In the future, I hope computers are finally used to their full potential to provide flexible instruction that adapts to the needs of the individual student. But within the confines of what Duo can do, perhaps more fleshed out lessons with more sentence variety would be helpful but that would be an incredible amount of work for you all.
I think it is important to point out also that a lot of the difficulties I see Duo Klingon students having are specifically because they are being lazy and expecting to be spoon fed without any personal responsibility to learn on their own. They clearly don't read the lesson notes. They don't look things up on their own. They ask a lot of questions about things that were taught many lessons prior as though it is something entirely new and it is clear that they have never put a single ounce of time into self study before trying to just bushwack through the tree. The rest of us should not be punished in order to make things easy for people who aren't willing to put the work in--are those people going to stick with Klingon anyway? Aren't the people who are going to keep studying Klingon over the years and attend conferences and take tests those of us who are willing to put in a little more effort at the beginning stage as well? People who only want things that come easy without paying any dues are quitters in my experience. I see so many questions asked that could be answered in under a minute of searching the internet or by having done the minimum of reading lesson notes. I'm not talking about people who are putting in effort but are confused. I mean there are a lot of people who are clearly low effort.
Another Klingon learner sent me a good idea. They said that the course should begin with a module of just individual vocabulary words. I like his idea. I think it would be good if the crown level 1 just introduced some of the basic words used in early in the course. Then each crown level could add more words. By the last crown level, all the beginner or intermediate test vocabulary could be added for people who want to be serious. My preference would be intermediate for the final crown. People who aren't serious can end at crown level 1 or where ever they want to minimally achieve their golden owl and not complain about difficulty. Other people would have the opportunity to advance as far in vocabulary as everything in TKD.
Do you have an estimated time of completion for tree 2? What happens to tree 1 then? Will you give us a heads up if tree 1 is going to disappear so we can review parts of it if we wish? Or if certain skills are going to be removed let us know so we can review those?
We have dreams about creating a new tree, but there are currently no plans. We are mostly working on audio and getting Duo to fix the probelms that still exist for us in the software. There may be some small changes in a tree 2, but they would be hardly noticable from the user side. Duo is trying to make all courses follow CEFR, which would be a bit of a challenge for Klingon, but I think could be done. And we could even work on mathcing closer with the KLCP. We would probably simplify the early lessons and move a little slower if we did a redesign like that. But people who want more of a challenge or are already familiar with the basics can always use the test out functions to keep things more challenging. Doing a major redesign like that would take a lot of work and will not show up any time soon.
It would be a monumental amount of work. I am personally ok with the tree as is. The more I have been thinking about it, the more I think if you ever do a tree 2 then varying the crown level difficulty would be the best option. The blue level could be easier than now. And then green, red...and so on could get increasingly difficult. That might have a chance at satisfying everybody somewhat.
If you do follow CEFR or try to match the KLCP, will that require more than small changes to the tree?
I understand the too slow book, but since this is an "alien" language, could you make an introductory lesson that tests the pure basics first, then compounds them in a later lesson? You guys are doing a great job considering you have a good, clear voice for the words and sentences.
Sometimes I forget to read them when first starting a new lesson, but yes, I've read them all, and I sometimes go back and re-read them too. I don't want to say they're not helpful, because they do help, but... like I indicated, I'm finding this more difficult than other courses, and that's with them.
All the languages you cited are part of the IndoEuropean language family which will be easier for you. When you go outside your primary language family, it becomes more challenging for most people. The military estimates for how many hours it takes to become proficient in a particular second language is based on what somebody's native language is.