If you’re writing an i18n-enabled Rails application, you have to deal with the translation of your own application as well as with the translation of several Rails core strings (like validation error messages, date formats, and so on). You usually don’t need to translate the Rails core strings yourself, since there’s a big repository of user-contributed core translations you can pull into your application. However keeping this translations up to date in your application can quickly become cumbersome.

For this reason, I refactored the rails-i18n(*) repository a while ago and made it a Rails plugin. You could install the plugin to your application and it provided Rails core translations for you. Unfortunately it became annoying to keep the fork up to date with the latest translation changes since every rebase or merge was a pain because of the moved file locations.

So my latest solution is another small plugin called rails-i18n-updater, which does not contain the translations itself but downloads them from the above mentioned repository of core translations.

Rails I18N gives you a way to translate your views and easily switch between different languages. However, you still need to set the locale for each request, i.e. you have to choose a method to select the right locale for a request. This can be done in various ways, depending on how you perfer it to behave. Here are some examples.

1. by browser-setting
2. by toplevel domain
3. by subdomain
4. by manual selection

Since Rails 2.2 has been released last week, lots of people are beginning to translate their applications — or, at least, many people seem to prepare their applications for later translation by replacing strings in views with t() calls.

If you’re modifying your application to be i18n-ready, or if you’re creating a new multilingual application, here’s a useful guideline to remember: translate meanings, not words.

Just a quick note that this blog is now running Rails 2.2 and makes use of the new i18n framework. Although this site is completely in English, the same application is also serving another blog in German. Moving the blog application from ruby-gettext translations to Rails i18n was quite a bit of work since the i18n simple backend works differently and after all, I had to recreate all translation files.

In the end, it works very well and reliable. While working with i18n views, I had some small ideas for improving translation handling in views – maybe I can come up with some minor improvements after thinking about it some more.

The main difference between gettext and Rails i18n is the usage of translation keys. With gettext, you place full strings of the “master language” (usually English) into the views. With Rails i18n, you build up a hierarchical structure of translation symbols (like “sidebar.latest.title”) and associate them with real text in translation files. Currently there’s no tool to extract symbols used in views to assist you to keep translations complete (like rgettext does for gettext), but I guess helpers will appear soon.

For my translations, I used the i18n simple backend, which comes with Rails and stores translation strings in simply .yml files. However, the Rails i18n framework actually is much more than just translations in .yml-files. It allows translation backends to hook into the Rails core with a documented interface, which promises to be more stable and reliable than monkeypatching solutions (e.g. like ruby-gettext does). In theory, it should be possible to create an i18n backend that utilizes gettext — which certainly is still very interesting e.g. to upgrade existing applications or for large applications with many translators (since the gettext format is widely supported by a lot of tools and services).

The next version of Rails (which most probably will be version 2.2) will come with an integrated internationalization (i18n) API. Here’s an overview of how this affects an application if you’ve used the gettext gem so far.

First of all, the new Rails i18n API isn’t meant to completely replace existing localization plugins like gettext. More precisely, it’s an API built into the Rails core to provide easier access for i18n plugins. The API, for example, makes it much easier to customize number, currency, date and time formats as well as error messages (e.g. in validations) and output of helpers like distance_of_time_in_words.