Russian letters in Ukrainian app translations: mostly not copy-paste

Description and use

In open Android apps on F‑Droid, 54 Ukrainian strings containing Russian-only letters were found across 39 apps. Most defects are Russian words or keyboard slip‑errors, not copied Russian strings.

Problem

Ukrainian strings in Android apps sometimes contain Russian-only letters, indicating untranslated or incorrectly typed text.

Outcome

Out of 302,844 Ukrainian strings, 54 contained Russian-only letters across 39 apps. Prediction P1 held, P2 failed, P3 held, P4 failed. Most defects were Russian words or keyboard slip‑errors, not copied Russian strings.

Workflow

• Pre‑register four predictions in PREREG.md
• Run AI agents to count Russian-only letters in Ukrainian/Belarusian strings on 1 Nov 2026
• Collect results in RESULTS.md
• Manually review 117 Ukrainian and Belarusian hits
• Classify each hit as mixed, whole Russian string, Belarusian string, or non‑defect

Evidence

Ukrainian has no ы, э, ё or ъ. Belarusian has no и or щ. Russian has all of them.

Source

So a Ukrainian string in an Android app that contains ы is, almost always, Russian showing through: a pasted Russian string, a Russian word, or a typo made with the Russian keyboard layout switched on.

Source

39 apps

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9 of 49

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6.7 vs 1.8 per 10,000 strings

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5.0 vs 1.8 per 10,000

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54 of 302,844 Ukrainian strings

Source