Pluralization in i18n Formats

Pluralization is a fundamental aspect of internationalization (i18n). Every language has its own rules for expressing quantities, and handling plurals correctly is essential for natural, high-quality translations. Locize supports pluralization for all major i18n formats, making it easy to manage plurals in your localization workflow.

Why Pluralization Matters

• Plural forms are required for accurate, natural-sounding translations in many languages.
• Incorrect pluralization is a common source of localization bugs and user confusion.
• Locize automates plural key generation and ensures the correct forms are available for each language and format.

Pluralization: Separate Keys vs. In-Format Handling

Some i18n formats require you to define separate translation keys for each plural form (e.g., item_one, item_other). Others, like ICU MessageFormat or Fluent, solve pluralization directly within the value of a single key using special syntax, so you do not need to create multiple keys for each form.

Summary:

• Requires separate keys: i18next, i18n.js, Android, Gettext
• Handled within the format (single key): ICU MessageFormat, Fluent, vue-i18n, polyglot.js

See the table below for details.

Supported i18n Formats and Pluralization

Locize supports pluralization for a wide range of i18n formats. For details on each format, see the main i18n formats page and file formats.

How Pluralization Works in Locize

• Locize automatically generates the required plural keys for each language and format (if required/necessary).
• The CAT view / Translation Editor displays all necessary plural forms for each key.
• Plural rules are based on the Unicode CLDR plural rules.
• You can preview and edit all plural forms directly in the Locize UI.

For more on why you might see keys like _one, _few, _many, _other, see this FAQ.

Format-Specific Examples

i18next JSON (separate keys)

{
  "item_one": "One item",
  "item_other": "{{count}} items"
}

ICU MessageFormat (single key)

{
  "item": "{count, plural, one {One item} other {{count} items}}"
}

Gettext PO (separate keys)

msgid "item"
msgid_plural "items"
msgstr[0] "One item"
msgstr[1] "{count} items"

Android XML (separate keys)

<plurals name="item">
  <item quantity="one">One item</item>
  <item quantity="other">%d items</item>
</plurals>

Fluent (single key)

item =
  { $count ->
    [one] One item
   *[other] { $count } items
  }

Best Practices for Pluralization

• Always use the pluralization features of your chosen i18n format.
• Avoid hardcoding plural forms in your code or translations.
• Test your app in languages with complex plural rules (e.g., Russian, Arabic).
• For more tips, see the i18next pluralization guide and Unicode CLDR plural rules.

Troubleshooting & FAQ

• Why do I see keys marked as ONE, FEW, MANY, OTHERS?
• How do I change the i18n format for my project?
• How do I import/export plural forms?
• Blog: I18N in the Multiverse of Formats