Localization

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Internationalization

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Internationalizing Strings in JavaScript

To internationalize a string in a 0 A.D. JavaScript file, simply use the following global functions:

translate(message);
translatePlural(singularMessage, pluralMessage, number);
translateWithContext(context, message);
translatePluralWithContext(context, singularMessage, pluralMessage, number);

These functions return the specified message translated into the current language. If that language is the source language or if there is no translation for the specified message, these functions return the specified message.

Using Plural Functions

Plural functions require that you pass them two versions of the same message: a message in singular form (number = 1) and a message in plural form (number != 1). This is because those are the English plural forms. However, other languages may have more plural forms or no plural forms at all. That is why you must specify an integer, number, that is the number of items represented in your message.

Using Context Functions

Context functions are used to handle cases where an English string may have a different meaning depending on the context. When that happens, chances are other languages use different words for each one of those meanings. If you use a context-free internationalization function (translate or translatePlural) to translate two messages that contain the same text, when you generate a translation template (POT file) from the sources, both messages are treated as a single message, and translators can only translate the message one way or another. If instead you use a context function (translateWithContext or translatePluralWithContext) and specify a different context for each message, translators will be able to translate each message differently.

The context string can be any short English string. The following is a real-life example, extracted from the game sources:

translateWithContext("map size", "Any");
translateWithContext("player number", "Any")

Usually, you do not need to worry about whether or not a string needs a context. You can always use a context-free internationalization function, and if a context is necessary for one or more languages to properly translate the message, translators will let you know, and you can then switch to a context function.

However, you might want to be alert for the following cases that might need a context:

• Single words. When you translate a single word, you are likely to need a context.
• Unclear verb tenses or nouns. More often than not, the same English word may represent two or more different tenses of a verb, and also work as a noun or other type of word. If the message string is not clear enough as to which of those tenses is being used or whether the word is working as a verb or as a different type of word, you need a context.

Using Format Strings Instead of Concatenating Strings in JavaScript

TODO: sprintf.

Internationalizing Objects

TODO: translateObjectKeys

Implementation Details

In the globalscripts folder of the public mod folder you can find the following two scripts: l10n.js and sprintf.js.

l10n.js implements the following global internationalization functions:

translate(message);
translatePlural(singularMessage, pluralMessage, number);
translateWithContext(context, message);
translatePluralWithContext(context, singularMessage, pluralMessage, number);
translateObjectKeys(object, keys);

The first four functions are simply wrappers for the engine internationalization functions (such as Engine.translate). These global functions use caching to reduce the number of calls to the engine functions, because calls to engine functions require string conversions that are far from cheap.

translateObjectKeys is a helper function that can translate specific properties (keys array) of a JavaScript object.

See Also

• ​Internationalization and localization (Wikipedia)