XLIFF

XLIFF [1] is the OASIS standard for translation.

Versions

The Translate Toolkit supports both XLIFF 1.x and XLIFF 2.0:

  • XLIFF 1.x (1.1 and 1.2) - Available via translate.storage.xliff

  • XLIFF 2.0 - Available via translate.storage.xliff2 (added in version 3.17.0)

Warning

XLIFF 2.0 is not compatible with XLIFF 1.x.

References

Flavours

XLIFF 1.2 also has documents that specify the conversion from various standard source documents and localisation formats.

Apple XLIFF

Apple has developed a custom variant of XLIFF 1.2 that encodes iOS/macOS .stringsdict plural information directly in XLIFF trans-units. This format is supported via translate.storage.applestrings_xliff.

The Apple XLIFF variant uses a special ID naming convention to represent plural forms:

  • key:variable:dict - Marks a plural variable (source: NSStringPluralRuleType)

  • key:variable:dict/:string - Specifies the format value type (e.g., d for integer)

  • key:variable:dict/PLURAL_FORM:dict/:string - Contains the actual plural form strings (e.g., one, other, zero)

Example

<?xml version="1.0" encoding="UTF-8"?>
<xliff xmlns="urn:oasis:names:tc:xliff:document:1.2" version="1.2">
  <file original="Localizable.strings" source-language="en" target-language="en">
    <body>
      <!-- Plural variable marker -->
      <trans-unit id="items:count:dict">
        <source>NSStringPluralRuleType</source>
        <target>NSStringPluralRuleType</target>
      </trans-unit>

      <!-- Format type -->
      <trans-unit id="items:count:dict/:string">
        <source>d</source>
        <target>d</target>
      </trans-unit>

      <!-- Plural forms -->
      <trans-unit id="items:count:dict/one:dict/:string">
        <source>One item</source>
        <target>One item</target>
      </trans-unit>
      <trans-unit id="items:count:dict/other:dict/:string">
        <source>%d items</source>
        <target>%d items</target>
      </trans-unit>
    </body>
  </file>
</xliff>

The Translate Toolkit parses Apple XLIFF files and folds each plural group (marker + format-type + individual form trans-units) into a single AppleStringsXliffUnit whose source and target are multistring objects. The strings list follows the same ordering as translate.lang.data.plural_tags() for the target language, with zero always included first (Apple convention).

This mirrors the behaviour of the Apple .stringsdict files format and makes Apple XLIFF plural units compatible with the rest of the Translate Toolkit’s plural pipeline.

Standard conformance

Done

  • File creation and parsing

  • API can create multiple files in one XLIFF (some tools only read the first file)

  • source-language attribute

  • trans-unit with

    • note: addnote() and getnotes()

    • state

      • fuzzy: isfuzzy() and markfuzzy()

      • translated: marktranslated()

      • approved

      • needs-review-translation: isreview(), markreviewneeded()

    • id: setid()

    • context-group: createcontextgroup()

  • context groups

  • alt-trans

XLIFF and other tools

Here is a small report on XLIFF support by Windows programs.