Counter/timer code for dates question

Hi,

I´m working on translating a wordpress theme. I have translated pretty much the whole teme exept one word.

If you can take a look at this page
You will see at the featured posts (named “hovedoppslag”)has a text similar to this “1 day siden” which in english means “1 day ago” in the upper left corner. This tells when it was posted.

As you can see I managed to translate the word “ago” to “siden” but not the word “day”

The counter/timer code which is used in the theme looks like this
<?php echo human_time_diff(get_the_time('U'), current_time('timestamp')) . __(' ago', 'themejunkie'); ?>

My question is: Can anybody tell me from where it gets the word “day”. Or how this code is build? from where does it gets its data?

Thanks in advance for helping out.