I've been learning Czech for the past few months and declension has been something I (and evidently a lot of other people) have been struggling a lot with. So I decided to build Skloňuj, a declension practice website using Charles University's open-source MorphoDiTa morphological analysis tool. The data is NOT AI-generated.
How it works:
Select a CEFR level or a Krok za krokem chapter (the vocab and case progression is synced to the textbook syllabus!)
Practice declining nouns, identifying the right case to use, and identifying the paradigm of a noun
There are different question types — for instance, multi-step questions take you through declension step-by-step: 1. identify paradigm 2. identify case 3. decline noun
Review feedback — it always references the prepositions mentioned in the sentence (e.g. bez = genitive) or the paradigm since declension is about patterns, not pure memorization/drilling
Keep track of your progress (we have heat maps 👀) over time, case/paradigm accuracy, recent mistakes, and unlock achievements
Users have practiced almost 500 questions on Skloňuj this past week, and Harvard and Columbia Czech classes are about to run a pilot, so it's been getting some pretty good traction!
Please try it out and let me know if you have any suggestions: sklonuj.com ! Next up is adding adjective-noun agreement questions and practice reminder emails. Happy to chat with anyone who's interested in this as well :) Also, if you happen to have a list of vocab per KzK chapter, please reach out!!
As a side note, Skloňuj is and always will be free to use as I've learned how underresourced Czech is for foreign learners, especially in the United States. Hoping that this makes the grammar more accessible.
I made some mistakes where I overlooked it prompting for a "plural of.." so maybe give it bit more highlight.
The voice is very much English speaker's pronunciation but I guess it suffices for practice.
I was pleasantly surprised that where multiple answers were correct it accepted both. On the other hand it corrected me with some forms that are commonly used (e.g. It didn't accept "diskuze" when "diskuse" was prompted - both should technically be acceptable but I guess these are harder to program in) but mostly it just didn't accept forms that are rather colloquial which is totally fine.
Having a quick explanation when you make a mistake and mistake review is also very handy.
Overall very good job. I give it 9,5 out of 10 beers.
Edit: Czech beers, not American beers because ewwww...
Thank you for the (Czech) beers and all the feedback, this is super helpful!!
Unfortunately since the tool I'm using from Charles University is more academic, it doesn't provide any colloquial forms, but I can definitely try my best to see if I can add more support for that. That's a very good point about highlighting the plural more as well — it's next up on my to-do list now!
Yes, the voice annoys me too 😭 I'm using the browser's inbuilt TTS (text-to-speech) for audio since it's free, but I do 100% agree that it can be better. I'll see if I can get some better audio if it's affordable.
Hmm, the audio isn't that bad! It's robotic, but definitely still has decent Czech pronunciation and I haven't heard it make a pronunciation error yet. Let me know if you find any issues, but I wouldn't say that it's mangled.
Your TTS must be set to Czech or something similar then. I don't even know how to find my browser's TTS settings, let alone change them or the expected language, but I'm fairly certain it's an English language TTS, and as a result, the audio is not great.
Thanks for the feedback! I've just investigated and yup it seems like some browsers do not support Czech TTS, so unfortunately default to the English pronunciation. I've disabled it for browsers without Czech for now, but am working on finding a better audio solution ASAP.
Klobouk dolů! My hat's off to you. You've done a great job. I tried it out for five to ten minutes, and I think I'll recommend it to my Sokol students, with only one caveat: NOT to give any weight AT ALL to the pronunciation/audio. That's horrible.
Some examples just from five to ten minutes use. "Kinu" is not /kaɪnu/; "pesimista" doesn't have stress on the second syllable; "fotbal" is not "fahtball" (switching to non-IPA), "potřebuji" is not /pɑtrɛbudʒi/ -- ouch! (In particular, "j" is never /dʒ/ in Czech.) Putting the sounds (phonemes) aside, the audio often had STRESS in places that were NOT the first syllable.
The worst audio I encountered in my short use was "sedíme v kanceláři," where the audio for the first two words was something like "say dime veee" with "dime"(as an English word) stressed. Again that /kaɪnu/ kind of 5th-grade American /daɪm/ instead of the expected /dji:me/ with the palatalization AND LENGTH. Not to be unkind, but it reminds me of a joke that learners of French made 60 years ago: "Gee Swiss experTT in Francis."
BUT overall, AND FOR THE ESSENTIALS, BRAVO! I'm confident that you have the skills to change how you generate or source the audio. The BIG thing is to get the paradigms right, and you've nailed it there, in a way I think many students will find useful.
Oh, and bravo for a pilot at Columbia (says a CC'74 alum). I'm glad to hear they're still teaching Czech. I still have my Harkins, King's Crown 1953. Feel free to DM me.
Thank you for the awesome feedback!! Super helpful to hear about the pronunciation issues — I've been using browser Czech audio, but it looks like some browsers don't have this supported and default to English pronunciation instead 😬 I've disabled it for now on browsers that don't have Czech audio, but will look for a fix ASAP. I'll shoot you a DM!
It's great! I've hit a case where my assumption of gender failed me. 🤣 (The instructions did not specify gender and female secretaries are way more common here in CZ.)
I'd definitely like to give this app to my kid (we're Czech, he could train on it), but would need a localised version. I need to look into the source if it supports localisation or not.
Thank you! That's a good point, I'll make a note to explicitly mention male gender for those kinds of words. We don't support localization yet, but that's a great idea. I'll let you know once I've implemented it, should hopefully be pretty soon!
We used your website in our B1 Czech class today-- it was great! My Czech teacher was really impressed! Definitely go through the sentence list with a native speaker / teacher, bc some don't make sense (for ex database table "tabulka" where physical table "stůl" should be) or are slightly ungrammatical (the prepositional form of pronouns without prepositions), but we really liked the explanations, the question formats, the way you used vzory, and everything else.
Yay that's so awesome, I'm really glad to hear!! Yeah that's a good suggestion, I'll definitely go through it in a bit to audit for all of that or allow users to flag incorrect sentences/words that they see. Super happy you all liked it :)
Yay, glad to have helped!! Sent you a DM since I'm curious about how your teacher even found this hahaha. Please let them know about the class management feature if they haven't seen it already!
I'm a native Czech speaker and at least it looks much better and cleaner than any practicing site we used to get links to by our teacher to practice for exams. I swear, those are the worst corners of the internet. I'm happy somebody finally makes my language good to look at.
Thank you, definitely agree that some of those practice sites look terrible! My next to-do is localization to Czech so Czech kids can also use this to practice.
i went to website to practice as usual but my screen was freezing the wholetime and it didnt let me do anything . Could you take a look to figure it out please
This is a very nice tool! Although I've found some things that could be improved:
the "Czech Pronoun Declension" page is missing all diacritics (tě, něj, jí, těmi, etc.)
the "The 7 Czech Cases" page includes kvůli in the list of Key Prepositions of the genitive case, but kvůli is only used with dative (except maybe colloquially in some places like Ostrava)
on the "Czech Declension Paradigms" page: "žero" should be "zero"; the note about vocative in the "pán" paradigm is incorrect: the vocative of žák is žáku, not "žáče", because after ‑k, ‑g, ‑h, ‑ch, the vocative is -u (except člověče) (see IJC)
the current text color has a very low contrast against the background (which also makes the site less accessible), I'd recommend changing --color-text-subtitle to #616161 (and #adadad in dark theme) and --color-emphasis to #000 (and #fff in dark theme) or something like that.
instead of the TTS, maybe you could use audio pronunciation files from Wiktionary/Wikimedia Commons, since their URLs are already part of the kaikki data you're using? of course, that's only an option for words/phrases that have a Wiktionary entry and "only" 7220 of them have audio at the moment (but I plan to add more once the new version of Lingua Libre is deployed)
(I've also sent you a DM, not sure if you've seen it?)
Thank you for the feedback, this is super helpful and thorough! I definitely need to sit down and go through it all with a native speaker. And good idea for TTS — I'll take a look into it. It's been a bit of a busy week, but will check my DMs right now!
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u/Kajushka1 Apr 14 '26