Your app just stopped working on my iPhone 15 Plus. It crashes and would not start
Captured on . See reviews on the App Store
DuolingoReported repeatedly
People lose a daily streak when the lesson will not load
5 people raised this across 4 weeks, on iOS.
iPhone users across five countries and four app versions.
In their own words
Neither app store gives a review a permanent public link, so each entry is a snapshot taken on the date shown and the link goes to the app's review listing.
A lot of bugs like no sounds, the word is different from what it pronounced
- about billing
- worked before an update
Captured on . See reviews on the App Store
There are so many broken activities with buttons that don't select, or don't produce any sound
Captured on . See reviews on the App Store
it also won't load kana or other character / writing lessons
- described a workaround
Captured on . See reviews on the App Store
I cannot progress beyond this point as the app keeps hanging after the lesson
- worked before an update
Captured on . See reviews on the App Store
What people do instead
- restart the app
- wait several minutes for a lesson to load
What you could do with this
These four are written from the reviews above. Everything else on this page is quoted or counted.
written
BUILD IT
A lesson that is fully on the device before it starts.
See how3 points
- Fetch the next lesson's audio while the current one is being answered
- Let a downloaded lesson run with no network at all
- Start with the audio failure reviewers report most
Why it might not workPre-caching audio for every path a learner might take is a lot of storage on a phone.
written
START IT
Offline-first practice for people with unreliable connections.
See how2 points
- A day of lessons downloaded in advance, sized for a small device
- Aimed at learners on prepaid data rather than home broadband
Why it might not workContent licensing, not engineering, is what usually stops this being built.
written
STUDY IT
Does an outage break a learning habit, or only pause it?
See how2 points
- Track return rates after a failed session versus a completed one
- Separate the streak's effect from the interruption's
Why it might not workThe platforms hold the retention data and have no reason to publish it.
written
WRITE IT
Gamified learning that punishes you for its own outage.
See how2 points
- Follow someone who lost a long streak to a loading screen
- Use the reviews where the lesson hangs rather than the learner quitting
Why it might not workStreak mechanics are written about a great deal; the turn is the outage, not the psychology.
Related challenges
Duolingo
People are interrupted mid-lesson by prompts they cannot close
Duo now forces users to use AI
Build itEvery interruption carries a close control, and it is tested.
Start itNot a company. This is a policy question, not a product gap.
Study itDoes an undismissable prompt change lesson completion?
Write itLearning interrupted by the thing that sells you learning.
Reported repeatedly
Duolingo
People who cancelled a trial were billed for the year anyway
just take hundreds of dollars off your card with no consent and no way to get it back
Build itA trial that names the charge date and the amount before it starts, and again before it lands.
Start itA subscription record kept outside whoever is selling the subscription.
Study itHow many people who believe they cancelled were still charged?
Write itThe week between cancelling and being charged for the year.
Early signal
Duolingo
People run out of energy before they finish two lessons
my app is broken and it's putting me at a huge disadvantage
Build itA free tier metered by time practised rather than by mistakes made.
Start itPractice software where the daily amount is fixed and paid for once.
Study itWhat happens to a practice habit when a meter sets the session length?
Write itThe lesson that stops in the middle of itself.
Early signal