How to translate mins, hours, days...

Hello,

What's the easiest way to translate: mins, hours, days, etc. -> http://192.95.3.168/~newinstr/pitanja-i-odgovori/user/seba-28/

<tr>
<th><?php _e( 'Member for', QA_TEXTDOMAIN ); ?></th>
<td><?php echo human_time_diff( strtotime( $userdata->user_registered ) ); ?></td>
</tr>

Regards,
Igor