You will need to edit the language string "pre_pinned" in "core_public_global" in the ACP.
ACP > Look & Feel > Manage Languages
You may need to unlock your language packs, to do this you need to do the following:
1. Navigate to your ACP
2. Hover over the Support Tab on your ACP nav bar
3. SQL Management > SQL Toolbox
4. Scroll to the bottom and put the following query in the "Run Query" Textbox
UPDATE core_sys_lang SET lang_protected = 0 WHERE lang_protected = 1
That should work for you.