Localizing Your Android App: A Practical Guide to Reaching More Users

My apps see 2-3x more installs from non-English markets after adding localization. For a solo developer, it's one of the most efficient growth levers — you're not building new features, you're opening existing ones to a larger audience.

Here's how to do it right.

The Foundation: strings.xml

All user-facing text belongs in

res/values/strings.xml

<!-- res/values/strings.xml — English (default) -->
<resources>
    <string name="app_name">TaskFlow</string>
    <string name="add_task">Add Task</string>
    <string name="task_completed">Task completed</string>
    <string name="delete_task_confirmation">Delete this task? This cannot be undone.</string>
    
    <!-- Plurals -->
    <plurals name="task_count">
        <item quantity="one">%d task</item>
        <item quantity="other">%d tasks</item>
    </plurals>
</resources>

<!-- res/values-es/strings.xml — Spanish -->
<resources>
    <string name="app_name">TaskFlow</string>
    <string name="add_task">Agregar tarea</string>
    <string name="task_completed">Tarea completada</string>
    <string name="delete_task_confirmation">¿Eliminar esta tarea? Esto no se puede deshacer.</string>
</resources>

Using Strings in Compose

// String resource
Text(text = stringResource(R.string.add_task))

// String with format argument
Text(text = stringResource(R.string.welcome_user, userName))

// Plural
Text(
    text = pluralStringResource(R.plurals.task_count, taskCount, taskCount)
)

// Annotation strings (rich text)
val annotatedString = buildAnnotatedString {
    append(stringResource(R.string.terms_prefix))
    withStyle(SpanStyle(color = MaterialTheme.colorScheme.primary)) {
        append(stringResource(R.string.terms_link_text))
    }
}

Which Languages to Prioritize

For global distribution, prioritize by potential market × effort:

English + these 7-8 languages covers 70%+ of Android users worldwide.

RTL Language Support

Arabic and Hebrew are right-to-left. Android handles most layout mirroring automatically, but you need to use the right attributes:

// Use start/end instead of left/right
modifier = Modifier.padding(start = 16.dp, end = 8.dp) // Not padding(left, right)

// Row with gravity — use Arrangement.Start not Arrangement.Left
Row(horizontalArrangement = Arrangement.Start) { ... }

<!-- In Manifest -->
<application android:supportsRtl="true">

Test RTL with: Settings → Developer Options → Force RTL layout direction.

Using Machine Translation as a Starting Point

Google Translate can produce a rough initial translation. For professional apps, have a native speaker review the output — machine translation often produces technically correct but unnatural text.

For validation without hiring translators, post in Reddit communities for each language (r/es, r/de, r/france) asking for translation feedback. Many users are happy to help if you ask nicely.

Android Studio has a built-in translation editor:

Open any

strings.xml

Locale-Specific Resources

Different locales need different resources beyond strings:

Date and time formats:

DateTimeFormatter.ofLocalizedDate()

Number formats:

NumberFormat.getInstance()

Currency:

NumberFormat.getCurrencyInstance()

formattedPrice

Images: Some regions have different cultural norms for imagery. Put locale-specific images in

res/drawable-es/

res/drawable-ja/

Detecting the Device Locale

// Current locale
val locale = if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.N) {
    context.resources.configuration.locales[0]
} else {
    @Suppress("DEPRECATION")
    context.resources.configuration.locale
}

val languageCode = locale.language // "en", "es", "ja"
val countryCode = locale.country   // "US", "MX", "JP"

For most apps, you don't need to detect the locale — Android applies the right strings.xml automatically based on the device language setting.

In-App Language Switcher (Android 13+)

Android 13 introduced per-app language preferences. Users can set a different language for your app than their system language:

// Check the current app language
val currentLocale = AppCompatDelegate.getApplicationLocales().get(0)

// Change the app language
AppCompatDelegate.setApplicationLocales(LocaleListCompat.forLanguageTags("es"))

Implement an in-app language picker in Settings if you want to support this explicitly. Otherwise, Android 13+ users can change the app language from system Settings → Apps → Your App → Language.

Play Store Listing Localization

Don't forget to localize the Play Store listing itself:

1. Play Console → Store Presence → Store Listing
2. Select a language → Translate title, short description, long description
3. Add locale-specific screenshots if possible

A Spanish user finding your app via a Spanish search sees Spanish listing text — and converts much better than seeing English.

Testing Localization

# Change device locale via ADB
adb shell settings put system language es
adb shell settings put system user_locales es-ES

# Restart the launcher for changes to take effect
adb shell am broadcast -a android.intent.action.LOCALE_CHANGED

Or change in Settings → System → Language.

Walk through your app's main flows in each supported language. Look for:

• Text that doesn't fit in buttons (German is notably long)
• Untranslated strings (defaulting to English)
• RTL layout issues (Arabic, Hebrew)

Takeaways

• All strings in
  code Copy

  strings.xml

  from day one — retrofitting is expensive
• English + Spanish, Portuguese, German, French, Japanese covers 70%+ of Android users
• Enable
  code Copy

  supportsRtl="true"

  and use
  code Copy

  start/end

  instead of
  code Copy

  left/right

• Machine translate as a starting point, native speaker review for shipped apps
• Localize your Play Store listing — it directly affects search ranking in those markets