Modifying 'New Thread' attributes

[ZiNgA BuRgA]

You can use the Language File Prefix option instead, if all you wish to change is the text.  You'll need to make copies of newthread.lang.php etc, modifying the text inside this copy.
It's nicer than modifying existing language files, since an upgrade won't trash your modifications, and since XThreads loads the default file before your modified version, even if new text is added in an upgrade, you won't need to update your modification.

If you wish to use custom templates, you could always just remove the {$lang->...} variable and enter the text directly.  The downside of using custom templates is that you may need to update them if you upgrade MyBB.