Make links on book navigation block Multilingual

You can use following code snippet for book navigation block in your module/theme if you want to hide the links that are not of the page's language.

Block languages

The Block languages module, part of the Internationalization (i18n) package, allows you to configure for which languages each block is visible. The settings for visibility per language are provided under Visibility Settings via the Languages tab when configuring a block.

Figure 1

The Languages tab also provides a setting for whether the block is translatable. For custom blocks, the block title and block content will be translatable. For blocks defined by modules, only the block title will be translatable. If Make this block translatable is selected, a Translate tab will appear for that block. This tab provides a UI for adding translations of the block in each available language.

Don't forget to allow your used string format to be translated on admin/config/regional/i18n/strings or you are going to have a error message like The string blocks:block:1:body for textgroup blocks is not allowed for translation because of its text format.

More infos http://hojtsy.hu/blog/2011-apr-03/drupal-7039s-new-multilingual-systems-...

Conflicts with Context

Internationalization (i18n) module

This is a complete manual and step-by-step guide for building multilingual websites with Drupal and the Internationalization (i18n) package.

Drupal 7.x has some built-in multilingual support to provide a localized user interface and translatable content. However, not everything is yet localizable/translatable. This package tries to fill the gaps that still exist. A few of the important features which the Internationalization package provides are:

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