Quick answer: Implement a fallback chain that tries the active locale, then the default locale, then the raw key, so a missing entry never produces empty UI.
An untranslated string should degrade to English, not to nothing. A small fallback chain in the lookup function prevents blank buttons and labels. Here is the fix.
How to fix it
1. Add a default-locale fallback
When the active locale has no entry for a key, retry the lookup in your default locale (usually English) before giving up, so partially translated languages stay usable.
2. Surface the key as a last resort
If even the default locale lacks the key, return the key string itself rather than empty text so the missing entry is visible and reportable instead of an invisible gap.
3. Log the miss for translators
Record every fallback hit with the key and locale so you can export a list of untranslated strings and feed it back to your translation team.
Catching the ones you can't reproduce
The hardest version of this to fix is the one you can't reproduce — it only happens on a player's hardware, OS, driver, or save state, under conditions that simply aren't present on your machine. A report that says “it crashed” or “it froze” gives you nothing to act on, so the bug survives release after release while quietly costing you players.
Automatic error capture closes that gap. Each failure arrives with its full stack trace, the device and OS, the build number, and a breadcrumb trail of what the player did right before it broke, so even a failure you have never seen becomes a specific, reproducible issue. Fold identical failures into one signature ranked by how many players each hits, and your worklist sorts itself worst-first instead of arriving as a stream of vague complaints.
This is where a tool like Bugnet earns its place. Its SDK captures every error automatically with the full stack trace plus device, OS, memory, build, and game-state context, folds duplicates into one grouped issue with an occurrence count, and ties each to the build it first appeared on — so you fix the problem that hurts the most players first and confirm it is gone when its signature disappears from the next release.
A crash you can name from its stack trace is a crash you can usually fix in minutes.