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

The String translation module, part of the Internationalization (i18n) package, provides support for other modules to translate user-defined strings. It implements the i18n_strings function, which in Drupal 6 was commonly known as the tt function. The i18n_strings function is an API function that lets other modules (such as the Taxonomy translation and Menu translation submodules) manage translations of user-entered strings. Depending on which modules you have enabled that use this feature, different text groups will be available for translation.

In contrast to Drupal's standard localization system, which always translates from English, strings will be translated from the source language. By default the source language is the site's default language, so changing the default language could break these translations. You can set which language is used as the source language via Administration > Configuration > Regional and language > Multilingual settings > Strings.

The Multilingual content module, part of the Internationalization (i18n) package, provides extended multilingual options for nodes. These options help accommodate a variety of translation workflows by controlling how the language for nodes is set.

Figure 1

Node Options per Content Type

For each content type, the following Extended language options are available under the Multilingual Settings tab (Figure 2):

• Set current language as default for new content can be useful for content that is community-generated.
• Require language prevents users from creating 'Language neutral' nodes.
• Lock language prevents users from changing the language of a node after it's created.

Additionally, if the String translation module is enabled, the Multilingual content module will localize all content type configuration texts including content type names and submission guidelines. Content type descriptions are localized by the core Locale module.

Figure 2

Site-wide Settings for Node Translation