Replacing Menu Link Name

[mac10]

How to replace the menu link names on the code:

Original code:
global $root_url,$lcl;
return '<li><a href="'.$root_url.'">'.$lcl['homepage'].'</a></li>
<li><a href="'.$root_url.'">'.$lcl['videos'].'</a></li>
<li><a href="'.$root_url.'?option=popular">'.$lcl['popularvideos'].'</a></li>
<li><a href="'.$root_url.'?option=contact">'.$lcl['contact'].'</a></li>';

to this:

global $root_url,$lcl;
return '<li><a href="'.$root_url.'">'.$lcl['Home'].'</a></li>
<li><a href="'.$root_url.'">'.$lcl['Videos'].'</a></li>
<li><a href="'.$root_url.'?option=popular">'.$lcl['Popular Videos'].'</a></li>
<li><a href="'.$root_url.'?option=contact">'.$lcl['Support'].'</a></li>';

****************************
Every time I replace the link names, the link disappears. Any help would be awesome!

Thanks

[admin]

open locale/en.php
end find
$lcl['homepage']
$lcl['videos']
$lcl['popularvideos']
$lcl['contact']

and chage teir values
do not touch function.php codes