Title / Slug swap

<?php } elseif (is_single()) { ?>
<?php $category = get_the_category(); $catlink = get_category_link( $category[0]->cat_ID ); echo ('<a href="'.$catlink.'">'.$category[0]->cat_name.'</a> '.'<span class="raquo">&raquo;</span> '.get_the_title()); ?>

gives me: Home ? Testimonial ? Anne & Chris

<?php } elseif (is_category()) { ?>
<?php if (is_category()) { $yourcat = get_category ($cat); echo ''.$yourcat->slug; } ?>

gives me: Home ? Testimonials

I’m wondering how I go about making the first snippet of code display slugs vs category titles. I always seem to end up with an error which ever way I shake it.

Any help would be greatly appreciated.