Hi,

To change ‘All Product’, please go to the file app\design\frontend\default\sns_nova\template\sns\producttabs\navs.phtml, find and replace the code bellow:
<span class="title-navi"><?php echo $item->title; ?>

By:

<span class="title-navi"><?php echo $this->__($item->title); ?>

After that, you can use feature Translate inline of Magento to change the text.

If you haven’t known this, please refer User guide of Magento, or you may see this link
https://www.youtube.com/watch?v=c5YQDJj0QbE

Thanks you,