The "course categories" show all languages one after another. The course names are displayed correctly.

Cf. MDL-25609

REPRODUCTION:

(1) Turn on multilang filter.
(2) Create some course categories using multilang code.
(3) Set "Combo List" as front page
(4) Go to the front page

FIX INSTRUCTIONS:

(1) Open course/renderer.php
(2) Go to line 112 and add a "format_string()" to "$category->name". The line should now look like this: $content .= html_writer::link(new moodle_url('/course/category.php', array('id'=>$category->id)), format_string($category->name), array('class'=>'category_link'));

For the course names it's already done (cf. l. 133 and cf. MDL-25609)