[How can change this font size lable in this code?]

Hi,

I have this code :

<li data-fss="Smaller,Small,Medium,Big,Bigger">

its used to change font size and in same time i shows size label with caps letters like this:-

i need to show another language label without losing code functionality of each wood, because it need the english label to work:-

<?php echo JText::_('LANG_FONT_SIZE_LABEL') ?>

  any idea?