Помогите правильно настроить модуль - i18n.
Я пробовал переводить сам, и переводчиком, но сути так и не понял.

1. Вот здесь: String translation:

When translating user defined strings that have an Input format associated, translators will be able to edit the text before it is filtered which may be a security risk for some filters. An obvious example is when using the PHP filter but other filters may also be dangerous.

As a general rule do not allow any filtered text to be translated unless the translators already have access to that Input format. However if you are doing all your translations through this site's translation UI or the Localization client, and never importing translations for other textgroups than default, filter access will be checked for translators on every translation page.

Important: After disallowing some Input format, use the refresh strings page so forbidden strings are deleted and not allowed anymore for translators.
Переводимые входные форматы:

Filtered HTML
Full HTML
PHP

В чём опасность перевода строк PHP, чем может быть опасен Full HTML.

2. За что отвечает эта настройка?

Content selection
Content selection mode:
-Current language and language neutral.
-Mixed current language (if available) or default language (if not) and language neutral.
-Only default language and language neutral.
-Only current language.
-All content. No language conditions apply.
-Determines which content to show depending on the current page language and the default language of the site.

Я выбрал Mixed, это как я понял Будет стоять язык документа по умолчанию, иначе любой другой. Непонятно.
Помогите выбрать правильную настройку.