What is the purpose of "[Developer] Accented English" (zz-ZZ) in Android?

Question

In Android KitKat, if I choose Settings > Language & Input > Language, the first choice I am offered is [Developer] Accented English. This replaces each Roman letter with an accented version. You can find a list of all the character mappings here. (It helps if you can read French).

What is the purpose of this setting? Is it just to show how characters can be mapped to other characters? Or can it be used productively (to create specific phonemes in text-to-speech output for example?

Answer 1

It's a technique called 'Pseudolocalization', and it's used to help test that an app is handling aspects of localization correctly.

The idea is that instead of waiting for an app's string resources to be translated into other languages - which could take some time - a "fake" pseudo-language is used instead. If the app behaves well against this fake translation, then chances are it will perform well with actual translations. There's different variations of pseudolocalization out there, but most tend to do some of the following:

• Add parens [ ... ] or other delimiters around the string: this makes it easier to ensure that strings are not getting clipped at either end.

• Replace regular characters with accented characters: if you see a string without accented characters, than that's a sign that it might be hardcoded instead of being treated as a localizable resource. (In the past, this was also used to ensure that apps could handle non-ASCII characters correctly and didn't lose data in code page translation, though this is less of an issue now that modern platforms support Unicode.)

• Add padding to the string: this is to simulate languages such as German which often have longer translations for the corresponding English string. If the padded string gets truncated instead of wrapping or flowing, then likely the German string will do similar.

• Add known-to-be-tricky characters to act as 'canaries': on some platforms, symbols from specific parts of the Unicode range may be added to ensure that they are handled or supported properly. For example, a Chinese character might be added to ensure that Chinese fonts are supported: if this ends up showing as an empty square, than that would indicate a problem. Other common 'canary' characters include code points from outside the BMP, or using Combining Characters.

One advantage of using pseudolocalization over actual translation is that the testing can be performed by someone who does not understand the target language: "[Àççôûñţ Šéţţîñĝš___]" still visually appears similar to the original English text "Account Settings". If you try using it with a Screen-Reader such as TalkBack, or other wise send pseudolocalized text to Text-to-speech, you'll likely get nonsense, since it will try to treat the accented characters as actual accented characters.